Question

我有一个问题，当我要将我的位图图像保存为PNG格式的SD卡时，代码总是返回一个错误，如下所述，我不知道为什么？请建议我正确的解决方案。

错误堆栈：

12-28 12:50:58.765: ERROR/AndroidRuntime(16977): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.greetingApp.common/com.greetingApp.common.Greeting}: java.lang.NullPointerException
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.os.Looper.loop(Looper.java:123)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread.main(ActivityThread.java:4627)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at java.lang.reflect.Method.invokeNative(Native Method)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at java.lang.reflect.Method.invoke(Method.java:521)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at dalvik.system.NativeStart.main(Native Method)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977): Caused by: java.lang.NullPointerException
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at com.greetingApp.common.Greeting.SaveData(Greeting.java:138)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at com.greetingApp.common.Greeting.onCreate(Greeting.java:78)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-28 12:50:58.765: ERROR/AndroidRuntime(16977):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

代码：

protected void SaveData() 
        {


          FrameLayout view = (FrameLayout)findViewById(R.id.frameLayout2);
          view.setDrawingCacheEnabled(true);
          view.buildDrawingCache();
          bm = view.getDrawingCache();

          OutputStream outStream = null;
           File file = new File(extStorageDirectory, "er.PNG");
           try {
            outStream = new FileOutputStream(file);
            bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
            outStream.flush();
            outStream.close();

            //Toast.makeText(AndroidWebImage.this, "Saved", Toast.LENGTH_LONG).show();

           } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            //Toast.makeText(AndroidWebImage.this, e.toString(), Toast.LENGTH_LONG).show();
           } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
           // Toast.makeText(AndroidWebImage.this, e.toString(), Toast.LENGTH_LONG).show();

            // TODO Auto-generated method stub

        }

提前致谢

Answer 1

确保此处没有空

 FrameLayout view = (FrameLayout)findViewById(R.id.frameLayout2);

最好在onCreate中获取id并在SaveData()

中使用它

FrameLayout view;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_xml);
        view = (FrameLayout)findViewById(R.id.frameLayout2);
}

现在，您可以在FrameLayout

中使用SaveData()的此视图实例

在android中将位图保存到SD卡时出错

1 个答案: