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方向改變后設置imageview

[英]Set imageview after orientation change

 原文  2015-07-05 08:04:37  9   4    android/ rotation/ imageview

問題描述

我有以下代碼，它正常工作，直到我旋轉手機。 然后我必須再次單擊以加載圖像，我知道當我們旋轉活動重新啟動時，我們有一些方法來存儲狀態並恢復它，但在我的情況下，你可以看到img文件是一個字符串作為它是隨機生成的。 那么如何在旋轉之前使用onConfigurationChanged（這似乎很容易理解）來恢復之前的圖像呢？ 

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);
    }

當我旋轉它是崩潰和加載或onClick沒有圖像正在加載.. 

> 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

4 個解決方案

解決方案1
 5 已采納  2015-07-07 20:02:27

看起來主要的問題是你對imgView.setOnClickListener()調用嵌套在if (savedInstanceState != null)情況下。

我通過取消嵌套單擊偵聽器並在資源名稱中添加下划線來查找代碼。 我使用了9個圖像，通過img_8.png命名為img_0.png ，然后放入drawable文件夾中。

我還添加了在啟動時加載隨機圖像的代碼。

之后，它會在點擊時成功加載另一個隨機圖像。 我還測試了屏幕旋轉，你現有的代碼工作得很好，無論我旋轉屏幕多少次，它都能保持當前圖像。

這是完全工作和測試的代碼： 

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);
    }
}

生成應用程序的日志，單擊ImageView以更改圖像，然后旋轉屏幕： 

 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

解決方案2
 2  2015-07-05 09:06:21

  1. 創建兩個類級變量來存儲當前隨機數並存儲圖像狀態，例如： - IsImageDownloaded （Boolean）
  2. 覆蓋OnInstanceSave()方法並捕獲當前隨機數和圖像狀態。
  3. （當你旋轉設備onCreate()將被再次調用）在onCreate()檢查是否isImageDownloaded真或假（如果條件）。 如果是，則獲取捕獲的隨機數並使用此隨機數再次顯示圖像。
  4. 您可以創建一個單獨的方法來加載特定隨機數的圖像，您可以在onClick()方法和if條件中使用此方法。

解決方案3
 1  2015-07-13 14:24:48

在清單中使用它。 

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

這將自己處理方向更改。 並刪除savedInstance編碼

解決方案4
 0  2015-07-14 07:24:09

您只需先將圖像存儲在本地，然后只需獲取此圖像並設置為旋轉時間。 這也將增加你的負載圖像的應用程序時間

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