Android |创建分级栏-yiteyi-C++库

RatingBar允许用户对某些产品进行评分。在下面的代码中 getRating（） 函数用于计算产品的评级。这个 getRating（） 函数返回双类型值。

null

在Android中创建分级栏涉及以下步骤：

创建一个新的android项目。
在活动主菜单中添加分级栏。xml。
添加按钮以调用操作。
使用文本视图显示评分。

要在应用程序中使用评级栏，我们将使用内置的评级栏小部件，因此第一步是将其导入到项目中。
在main活动中，创建由变量“rt”表示的RatingBar对象，并在XML文件中找到相应的视图。这是通过findViewById（）方法完成的。java对象成功绑定到其视图后，创建用户将与之交互的“stars”布局，以设置评级。
要获取可绘制的星星，使用方法rt.getProcessDrawable（）。然后使用setColorFilter（）方法和参数Color来修改星星的颜色。黄色通过了。最后，编写Call方法以通过rt.getMethod（）方法提取用户选择的评级值。

创建MainActivity的程序：

                       // Below is the code for MainActivity.java                     
                       package                                  com.example.hp.rating;                     
                                
                       // importing required libraries                     
                       import                                  android.graphics.Color;                     
                       import                                  android.graphics.PorterDuff;                     
                       import                                  android.graphics.drawable.LayerDrawable;                     
                       import                                  android.support.v7.app.AppCompatActivity;                     
                       import                                  android.os.Bundle;                     
                       import                                  android.view.View;                     
                       import                                  android.widget.RatingBar;                     
                       import                                  android.widget.TextView;                     
                                
                       public                                  class                                  MainActivity                                  extends                                  AppCompatActivity {                     
                       RatingBar rt;                     
                                             @Override                     
                                             protected                                  void                                  onCreate(Bundle savedInstanceState) {                     
                                             super                                  .onCreate(savedInstanceState);                     
                                             setContentView(R.layout.activity_main);                     
                                
                                             //binding MainActivity.java with activity_main.xml file                     
                                             rt = (RatingBar) findViewById(R.id.ratingBar);                     
                                
                                             //finding the specific RatingBar with its unique ID                     
                                             LayerDrawable stars=(LayerDrawable)rt.getProgressDrawable();                     
                                
                                             //Use for changing the color of RatingBar                     
                                             stars.getDrawable(                                  2                                  ).setColorFilter(Color.YELLOW, PorterDuff.Mode.SRC_ATOP);                     
                                             }                     
                                
                                             public                                  void                                  Call(View v)                     
                                             {                     
                                             // This function is called when button is clicked.                     
                                             // Display ratings, which is required to be converted into string first.                     
                                             TextView t = (TextView)findViewById(R.id.textView2);                     
                                             t.setText(                                  "You Rated :"                                  +String.valueOf(rt.getRating()));                     
                                             }                     
                       }                     

注：对于布局，如果你是初学者，ConstraintLayout很适合使用，因为它可以根据屏幕调整视图。这个XML文件定义了应用程序的视图。

为MainActivity创建布局的程序：

                       <?                                  xml                                  version                                  =                                  "1.0"                                  encoding                                  =                                  "utf-8"                                  ?>                     
                       <                                  android.support.constraint.ConstraintLayout                     
                                             xmlns:android                                  =                                  "                         http://schemas.android.com/apk/res/android                        "                     
                                             xmlns:tools                                  =                                  "                         http://schemas.android.com/tools                        "                     
                                             xmlns:app                                  =                                  "                         http://schemas.android.com/apk/res-auto                        "                     
                                
                                             <!-- Cover the entire width of the screen -->                     
                                             android:layout_width="match_parent"                     
                                             <!-- Cover the entire height of the screen -->                     
                                             android:layout_height="match_parent"                     
                                
                                             tools:context="com.example.hp.rating.MainActivity"                     
                                             android:background="@color/colorPrimary">                     
                                
                                             <                                  RatingBar                     
                                             android:id                                  =                                  "@+id/ratingBar"                     
                                             android:layout_width                                  =                                  "wrap_content"                     
                                             android:layout_height                                  =                                  "wrap_content"                     
                                             android:layout_marginTop                                  =                                  "104dp"                     
                                             android:background                                  =                                  "@color/colorPrimary"                     
                                             app:layout_constraintLeft_toLeftOf                                  =                                  "parent"                     
                                             app:layout_constraintRight_toRightOf                                  =                                  "parent"                     
                                             app:layout_constraintTop_toTopOf                                  =                                  "parent"                     
                                             tools:layout_constraintLeft_creator                                  =                                  "1"                     
                                             tools:layout_constraintRight_creator                                  =                                  "1"                     
                                             tools:layout_constraintTop_creator                                  =                                  "1"                                  />                     
                                
                                             <                                  TextView                     
                                             android:id                                  =                                  "@+id/textView"                     
                                             android:layout_width                                  =                                  "wrap_content"                     
                                             android:layout_height                                  =                                  "wrap_content"                     
                                             android:text                                  =                                  "Rate Me!!!"                     
                                             android:textColor                                  =                                  "@android:color/background_dark"                     
                                             android:textSize                                  =                                  "30sp"                     
                                             android:textStyle                                  =                                  "bold|italic"                     
                                             tools:layout_editor_absoluteX                                  =                                  "127dp"                     
                                             tools:layout_editor_absoluteY                                  =                                  "28dp"                                  />                     
                                
                                             <                                  TextView                     
                                             android:id                                  =                                  "@+id/textView2"                     
                                             android:layout_width                                  =                                  "wrap_content"                     
                                             android:layout_height                                  =                                  "wrap_content"                     
                                             android:layout_marginTop                                  =                                  "148dp"                     
                                             android:textColorHint                                  =                                  "@color/colorAccent"                     
                                             android:textSize                                  =                                  "24sp"                     
                                             app:layout_constraintLeft_toLeftOf                                  =                                  "parent"                     
                                             app:layout_constraintRight_toRightOf                                  =                                  "parent"                     
                                             app:layout_constraintTop_toBottomOf                                  =                                  "@+id/ratingBar"                     
                                             tools:layout_constraintRight_creator                                  =                                  "1"                     
                                             tools:layout_constraintLeft_creator                                  =                                  "1"                                  />                     
                                
                                             <                                  Button                     
                                             android:id                                  =                                  "@+id/button"                     
                                             android:layout_width                                  =                                  "wrap_content"                     
                                             android:layout_height                                  =                                  "wrap_content"                     
                                             android:layout_marginBottom                                  =                                  "50dp"                     
                                             android:layout_marginTop                                  =                                  "50dp"                     
                                             android:background                                  =                                  "@android:color/holo_red_dark"                     
                                             android:onClick                                  =                                  "Call"                     
                                             android:text                                  =                                  "Submit"                     
                                             android:textColor                                  =                                  "@android:color/background_light"                     
                                             android:textStyle                                  =                                  "bold|italic"                     
                                             app:layout_constraintBottom_toTopOf                                  =                                  "@+id/textView2"                     
                                             app:layout_constraintLeft_toLeftOf                                  =                                  "parent"                     
                                             app:layout_constraintRight_toRightOf                                  =                                  "parent"                     
                                             app:layout_constraintTop_toBottomOf                                  =                                  "@+id/ratingBar"                     
                                             tools:layout_constraintBottom_creator                                  =                                  "1"                     
                                             tools:layout_constraintLeft_creator                                  =                                  "1"                     
                                             tools:layout_constraintRight_creator                                  =                                  "1"                     
                                             tools:layout_constraintTop_creator                                  =                                  "1"                                  />                     
                       </                                  android.support.constraint.ConstraintLayout                                  >                     

在这里，我们不需要更改清单文件，不需要对 分级杆 。默认情况下，清单文件中会提到所有创建的新活动。

以下是AndroidManifest的代码。xml

                       <?                                  xml                                  version                                  =                                  "1.0"                                  encoding                                  =                                  "utf-8"                                  ?>                     
                       <                                  manifest                                  xmlns:android                                  =                                  "                         http://schemas.android.com/apk/res/android                        "                     
                                             package                                  =                                  "com.example.hp.rating"                                  >                     
                                
                                             <                                  application                     
                                             android:allowBackup                                  =                                  "true"                     
                                             android:icon                                  =                                  "@mipmap/ic_launcher"                     
                                             android:label                                  =                                  "@string/app_name"                     
                                             android:roundIcon                                  =                                  "@mipmap/ic_launcher_round"                     
                                             android:supportsRtl                                  =                                  "true"                     
                                             android:theme                                  =                                  "@style/AppTheme"                                  >                     
                                             <                                  activity                                  android:name                                  =                                  ".MainActivity"                                  >                     
                                             <                                  intent-filter                                  >                     
                                             <                                  action                                  android:name                                  =                                  "android.intent.action.MAIN"                                  />                     
                                
                                             <                                  category                                  android:name                                  =                                  "android.intent.category.LAUNCHER"                                  />                     
                                             </                                  intent-filter                                  >                     
                                             </                                  activity                                  >                     
                                             </                                  application                                  >                     
                                
                       </                                  manifest                                  >                     

输出： 图片[1]-Android |创建分级栏-yiteyi-C++库

文章版权归作者所有，未经允许请勿转载。

THE END