android – Nullpointerexcepiton在光标上从对话框片段的画廊中选择照片

概述我正试图通过DialogFragment从图库中选择照片.但是我在初始化游标时遇到了nullpointerexception.任何想法为什么会出现此错误？ 以下是我的代码： if (resultCode == Activity.RESULT_OK) { Uri selectedImage = imageReturnedIntent.getData(); String 我正试图通过DialogFragment从图库中选择照片.但是我在初始化游标时遇到了nullpointerexception.任何想法为什么会出现此错误？

以下是我的代码：

if (resultCode == Activity.RESulT_OK) {        Uri selectedImage = imageReturnedIntent.getData();        String[] filePathColumn = {MediaStore.Images.Media.DATA};        // Nullpointerexcepiton on this line        Cursor cursor = getActivity().getContentResolver().query(selectedImage,filePathColumn,null,null);        cursor.movetoFirst();        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);        cursor.close();    }

这是我的logcat错误：

03-24 12:34:37.645: E/AndroIDRuntime(21479): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null,request=65538,result=-1,data=Intent { dat=content://media/external/images/media/3890 flg=0x1 }} to activity {com.example/com.example.MainActivity}: java.lang.NullPointerException    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread.deliverResults(ActivityThread.java:3462)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread.handleSendResult(ActivityThread.java:3505)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread.access00(ActivityThread.java:150)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread$H.handleMessage(ActivityThread.java:1346)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.os.Handler.dispatchMessage(Handler.java:99)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.os.Looper.loop(Looper.java:213)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread.main(ActivityThread.java:5225)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at java.lang.reflect.Method.invokeNative(Native Method)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at java.lang.reflect.Method.invoke(Method.java:525)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at com.androID.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at com.androID.internal.os.ZygoteInit.main(ZygoteInit.java:557)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at dalvik.system.NativeStart.main(Native Method)    03-24 12:34:37.645: E/AndroIDRuntime(21479): Caused by: java.lang.NullPointerException    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at com.example.MainDialogFragment.onActivityResult(MainDialogFragment.java:226)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at com.example.MainActivity.onActivityResult(DelictActivity.java:85)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.Activity.dispatchActivityResult(Activity.java:5322)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    at androID.app.ActivityThread.deliverResults(ActivityThread.java:3458)    03-24 12:34:37.645: E/AndroIDRuntime(21479):    ... 11 more

解决方法@H_404_24@ 你如何开始你的活动,从哪里开始？
如果您通过MainActivity传递结果,可以尝试在DialogFragment中创建一个新函数,如下所示：

public voID onMyActivityResult(Context main,int resultCode... an so on){     main.getContentResolver.......}

编辑：
我这样做了：

获取onCreate中的活动：

@OverrIDe    public voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    mActivity = (MainActivity) this.getActivity();    }

然后：

@OverrIDe    public voID onActivityResult(int requestCode,int resultCode,Intent data) {       if (requestCode == REQUEST_galLERY && resultCode == Activity.RESulT_OK) {           ...            Uri selectedImage = data.getData();            String path = getRealPathFromURI(selectedImage);           ...            reloadImages();        }        super.onActivityResult(requestCode,resultCode,data);        }

和：

private String getRealPathFromURI(Uri contentURI) {    Cursor cursor = mActivity.getContentResolver().query(contentURI,null);    if (cursor == null) { // Source is DropBox or other similar local file                  // path        return contentURI.getPath();    } else {        cursor.movetoFirst();        int IDx = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);        String path = cursor.getString(IDx);        cursor.close();        return path;    }    }

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