在改变方向后设置imageview

我有下面的代码，它正常工作，直到我旋转我的手机。然后，我必须再次点击加载图像，我明白，当我们旋转活动重新启动，我们有一些方法来存储状态，并恢复它，但在我看来，因为你可以看到img文件是在一个字符串为它是随机产生的。那么我怎样才能利用onConfigurationChanged（这似乎很容易理解）恢复之前的图像旋转之前？在改变方向后设置imageview

public class HomeScreen extends Activity { 

    protected ImageView imgView; 
    protected String str; 

    @Override 
    protected void onCreate(final Bundle savedInstanceState) { 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_home_screen); 
     final Random rnd = new Random(); 
     ActionBar actionBar = getActionBar(); 
     actionBar.hide(); 

     imgView = (ImageView) findViewById(R.id.imgRandom); 

     if (savedInstanceState != null) { 
      str = savedInstanceState.getString("param"); 
      imgView.setImageDrawable 
        (
          getResources().getDrawable(getResourceID(str, "drawable", getApplicationContext())) 
        ); 




      imgView.setOnClickListener(new View.OnClickListener() { 
       @Override 
       public void onClick(View view) { 



        // final ImageView img = (ImageView) findViewById(R.id.imgRandom); 
        // I have 3 images named img_0 to img_2, so... 
        str = "img" + rnd.nextInt(9); 
        imgView.setImageDrawable 
          (
            getResources().getDrawable(getResourceID(str, "drawable", getApplicationContext()))); 


       } 


      }); 


     } 
    } 

    protected void onSaveInstanceState(Bundle savedInstanceStat) { 
     super.onSaveInstanceState(savedInstanceStat); 
     savedInstanceStat.putString("param", str); 
    }

当我旋转它的崩溃，也对负载或无的onClick图像加载..

> 07-07 21:11:32.950: I/InputReader(468): Device reconfigured: id=1, 
> name='Genymotion Virtual Input', size 1080x1920, orientation 0, mode 
> 1, display id 0 07-07 21:11:32.950: I/ActivityManager(468): Config 
> changes=480 {1.0 310mcc260mnc en_US ?layoutDir sw360dp w360dp h567dp 
> 480dpi nrml port finger qwerty/v/v dpad/v s.14} 07-07 21:11:33.081: 
> W/ResourceType(1861): Too many attribute references, stopped at: 
> 0x01010034 07-07 21:11:33.081: W/ResourceType(1861): Too many 
> attribute references, stopped at: 0x01010034 07-07 21:11:33.082: 
> D/AndroidRuntime(1861): Shutting down VM 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): FATAL EXCEPTION: main 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): Process: 
> app.motivation.techiequickie.ypb.motivation, PID: 1861 07-07 
> 21:11:33.083: E/AndroidRuntime(1861): java.lang.RuntimeException: 
> Unable to start activity 
> ComponentInfo{app.motivation.techiequickie.ypb.motivation/app.motivation.techiequickie.ypb.motivation.HomeScreen}: 
> java.lang.NullPointerException: name is null 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): at 
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.app.ActivityThread.access$900(ActivityThread.java:151) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861):  at 
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.os.Handler.dispatchMessage(Handler.java:102) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861):  at 
> android.os.Looper.loop(Looper.java:135) 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): at 
> android.app.ActivityThread.main(ActivityThread.java:5254) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861):  at 
> java.lang.reflect.Method.invoke(Native Method) 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): at 
> java.lang.reflect.Method.invoke(Method.java:372) 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): at 
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861): Caused by: 
> java.lang.NullPointerException: name is null 07-07 21:11:33.083: 
> E/AndroidRuntime(1861): at 
> android.content.res.Resources.getIdentifier(Resources.java:2034) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861):  at 
> app.motivation.techiequickie.ypb.motivation.HomeScreen.getResourceID(HomeScreen.java:148) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> app.motivation.techiequickie.ypb.motivation.HomeScreen.onCreate(HomeScreen.java:35) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.app.Activity.performCreate(Activity.java:5990) 07-07 
> 21:11:33.083: E/AndroidRuntime(1861):  at 
> android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): at 
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278) 
> 07-07 21:11:33.083: E/AndroidRuntime(1861): ... 11 more 07-07 
> 21:11:33.084: W/ActivityManager(468): Force finishing activity 1 
> app.motivation.techiequickie.ypb.motivation/.HomeScreen

来源

2015-07-05 JackyBoi

请删除评论和重新格式化您的代码来创建一个[最小示例]（http://stackoverflow.com/help/mcve）。 – Seb

它看起来像主要问题是您拨打imgView.setOnClickListener()嵌套在您的if (savedInstanceState != null)案件。

我通过取消嵌套单击侦听器并向资源名称添加下划线来查找代码。我使用了九个图像，分别命名为img_0.png到img_8.png，然后放在drawable文件夹中。

我还添加了启动时加载随机图像的代码。

之后，它点击成功加载另一个随机图像。我还测试了屏幕旋转，并且您现有的代码工作得很好，无论我旋转屏幕多少次，它都会保留当前图像。

这里是全工作和测试代码：

public class HomeScreen extends Activity { 

    protected ImageView imgView; 
    protected String str; 

    @Override 
    protected void onCreate(final Bundle savedInstanceState) { 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_home_screen); 
     final Random rnd = new Random(); 
     //ActionBar actionBar = getActionBar(); 
     //actionBar.hide(); 

     imgView = (ImageView) findViewById(R.id.imgRandom); 


     if (savedInstanceState != null) { 
      str = savedInstanceState.getString("param"); 
      Log.d("image screen rotation", str); 
      imgView.setImageDrawable 
        (
          getResources() 
          .getDrawable(getResourceID(str, "drawable", getApplicationContext())) 
        ); 
     } 
     else{ 
      str = "img_" + rnd.nextInt(9); 
      Log.d("image startup", str); 
      imgView.setImageDrawable(
        getResources() 
          .getDrawable(getResourceID(str, "drawable", getApplicationContext()))); 
     } 

     imgView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 


       // final ImageView img = (ImageView) findViewById(R.id.imgRandom); 
       // I have 3 images named img_0 to img_2, so... 
       str = "img_" + rnd.nextInt(9); 
       Log.d("image click", str); 
       imgView.setImageDrawable(
         getResources() 
         .getDrawable(getResourceID(str, "drawable", getApplicationContext()))); 

      } 
     }); 


    } 

    protected final static int getResourceID 
      (final String resName, final String resType, final Context ctx) 
    { 
     final int ResourceID = 
       ctx.getResources().getIdentifier(resName, resType, 
         ctx.getApplicationInfo().packageName); 
     if (ResourceID == 0) 
     { 
      throw new IllegalArgumentException 
        (
          "No resource string found with name " + resName 
        ); 
     } 
     else 
     { 
      return ResourceID; 
     } 
    } 


    @Override 
    protected void onSaveInstanceState(Bundle savedInstanceStat) { 
     super.onSaveInstanceState(savedInstanceStat); 
     savedInstanceStat.putString("param", str); 
    } 
}

从运行的应用程序，点击的ImageView来改变图像，然后旋转屏幕生成的日志：

D/image startup﹕ img_8 
D/image screen rotation﹕ img_8 
D/image screen rotation﹕ img_8 
D/image click﹕ img_3 
D/image screen rotation﹕ img_3 
D/image screen rotation﹕ img_3 
D/image screen rotation﹕ img_3 
D/image screen rotation﹕ img_3 
D/image click﹕ img_7 
D/image screen rotation﹕ img_7 
D/image screen rotation﹕ img_7 
D/image screen rotation﹕ img_7 
D/image screen rotation﹕ img_7 
D/image screen rotation﹕ img_7 
D/image screen rotation﹕ img_7

来源

2015-07-07 20:02:27

不完全..原因..我的资源确实没有_，但我的原始代码工作，如果我没有嵌套IF保存实例方法中的onClick方法。但是，urs也能正常工作。 – JackyBoi

@jackyBoi我注意到了！我认为当你剥离代码时它一定是复制/粘贴错误。我会针对问题的真正原因更新答案！ –

好的解决方案，但它可以简化。 –

创建两个一流水平的变量来存储当前的随机数和存储图像状态，例如： - IsImageDownloaded（布尔型）
重写OnInstanceSave()方法并捕获当前随机数和图像状态。
（当您旋转设备onCreate()将被再次调用）在onCreate()检查是否isImageDownloaded真或假（如条件）。如果是，则获取捕获的随机数并使用此随机数再次显示图像。
您可以创建一个单独的方法来为特定的随机数加载图像，并且您可以在onClick()方法中以及在if条件中使用此方法。

来源

2015-07-05 09:06:21

使用这在你的清单中。

<activity 
     android:name="youractivity" 
     android:configChanges="keyboardHidden|screenSize|orientation" > 
    </activity>

这将自行处理方向更改。并删除savedInstance编码

来源

2015-07-13 14:24:48 Bunny

只需您可以将图像存储在本地的第一个，然后只是得到这个图像和旋转时间或其他设置。这也将增加你的应用程序的时间负载图像

来源

2015-07-14 07:24:09

在改变方向后设置imageview

回答

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