Question

Android新手。我有一个Activity，它创建了一些N个自定义视图。它创建的每个自定义视图都会添加到活动LinearLayout并显示在屏幕上。这可以正常工作，直到我旋转屏幕。突然，自定义视图无法正确显示其数据。在我的测试场景中，Activity创建了我的自定义视图的2个实例，第一个显示“Name 1”，而第二个在每个自定义视图的EditText中显示“Name 2”。当我切换方向时（这完全在我的Nexus 7上完成），两个自定义视图的EditText都说“名称2”。我在自定义视图的Activity和构造函数中使用了println语句，以确保仍然传入正确的值，但它只是以不同的方式显示。有任何想法吗？这是一些简化的代码：

public class EditTemplateWorkout extends Activity{

private int templateWorkoutId = -1;
private TemplateWorkout templateWorkout;

@SuppressWarnings("unchecked")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_edit_template);
    Intent intent = this.getIntent();
    templateWorkoutId = intent.getIntExtra(Messages.TEMPLATEWORKOUTID_MESSAGE, -1);                 
    templateWorkout = templateWorkoutId == -1 ? new TemplateWorkout() : LiftDroidDbHelper.TemplateWorkoutService.get(templateWorkoutId, true, this);            
    final EditText editTextName = (EditText) this.findViewById(R.id.editTextName);        
    editTextName.setText(templateWorkout.getName());
    editTextName.addTextChangedListener(new TextWatcher() {
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {                
            if(!s.equals("") ){ 
                String txtVal = editTextName.getText().toString();                  
                templateWorkout.setName(txtVal);
            }
        }
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {

        }
        public void afterTextChanged(Editable s) {

        }
    });

    LinearLayout root = (LinearLayout)this.findViewById(R.id.rootLayout);   
    root.removeAllViews();      
    for(TemplateExercise te : templateWorkout.getTemplateExercises()){
        root = (LinearLayout)this.findViewById(R.id.rootLayout);

        System.out.println("activity adding view for "+te.getName());
        EditTemplateExerciseView editTemplateExercise = new EditTemplateExerciseView(te, this, null);                   
        editTemplateExercise.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
        root.addView(editTemplateExercise);
    }

    int moot = 3;
}

}

public class EditTemplateExerciseView extends LinearLayout {

TemplateExercise templateExercise;  

public EditTemplateExerciseView(TemplateExercise te, Context context, AttributeSet attrs) {
    super(context, attrs);      
    templateExercise = te;
    setOrientation(LinearLayout.HORIZONTAL);
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    inflater.inflate(R.layout.view_edit_template_exercise, this, true);
    TextView txtName = (TextView) this.findViewById(R.id.templateExerciseNameTxt);        
    txtName.setText(templateExercise.getName() + templateExercise.getTemplateExerciseID());        
    System.out.println("templateXercise id ="+te.getTemplateExerciseID());
    System.out.println("set name:"+templateExercise.getName() + ", confirmed val="+txtName.getText());

}//constructor      

}

以下是我简化的自定义视图的副本：

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name:"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/templateExerciseNameTxt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10" >

        <requestFocus />
    </EditText> 
</LinearLayout>    
</merge>

以下是截图的链接： http://imgur.com/a/2HqmS

以下是代码在呈现良好预期视图时的原始输出结果：

01-17 17:44:49.588: I/System.out(22474): activity adding view for Bench Press
01-17 17:44:49.618: I/System.out(22474): templateXercise id =4
01-17 17:44:49.618: I/System.out(22474): set name:Bench Press, confirmed val=Bench  Press4
01-17 17:44:49.618: I/System.out(22474): activity adding view for Incline Bench
01-17 17:44:49.648: I/System.out(22474): templateXercise id =6
01-17 17:44:49.648: I/System.out(22474): set name:Incline Bench, confirmed val=Incline Bench6

当屏幕方向改变并调用Activity的onCreate方法时，以下是代码的println输出结果：

01-17 17:45:31.568: I/System.out(22474): activity adding view for Bench Press
01-17 17:45:31.588: I/System.out(22474): templateXercise id =4
01-17 17:45:31.588: I/System.out(22474): set name:Bench Press, confirmed val=Bench   Press4
01-17 17:45:31.588: I/System.out(22474): activity adding view for Incline Bench
01-17 17:45:31.618: I/System.out(22474): templateXercise id =6
01-17 17:45:31.618: I/System.out(22474): set name:Incline Bench, confirmed val=Incline Bench6
01-17 17:45:31.648: W/IInputConnectionWrapper(22474): showStatusIcon on inactive InputConnection
01-17 17:45:31.808: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection
01-17 17:45:31.878: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection
01-17 17:45:31.978: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection
01-17 17:45:32.178: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection
01-17 17:45:32.318: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection
01-17 17:45:32.338: W/IInputConnectionWrapper(22474): getTextBeforeCursor on inactive InputConnection

您可以看到我将预期值传递到第一个自定义视图，但它显示了第二个自定义视图的值。您在此处看到的代码与最初的视图相比大大简化了。任何机器大师都知道我在做错了什么？

Answer 1

你需要它保存你的CustomViews状态，当你改变设备的方向时，android OS从头开始初始化你的视图，所以尝试在你的视图方法中实现

onSaveInstanceState

将在方向更改之前由onpause方法调用，此处您将从edittext

保存数据

和

onRestoreInstanceState

将在完成定位后调用，并将正确的数据添加到您的视图

这里是完整代码：

How to prevent custom views from losing state across screen orientation changes

屏幕方向更改时，Android复合视图呈现错误

1 个答案: