空指针文件URI上的异常? [英] Null pointer Exception on file- URI?
本文介绍了空指针文件URI上的异常?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在我的应用程序中,有一个捕获按钮可以使用设备相机捕获图像,因此我对该按钮的click事件使用了captureImage()方法.当我单击该按钮时,将引发空指针异常.不明白这是怎么发生的,有人可以帮忙吗?预先感谢!
In my app a capture button is there to capture an image using device camera,so I have used a method captureImage() on the click event of that button.When I click the button a null pointer exception is thrown.I could not understand how this happens Can anyone help? Thanks in advance!
Create()方法上的捕获"按钮
capture button on on Create () method
photoButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/*
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);*/
captureImage();
}
});
captureImage()方法
captureImage() method
private void captureImage() {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
// start the image capture Intent
startActivityForResult(intent, CAMERA_REQUEST);
}
此方法的空指针异常
public Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
/**
* returning image / video
*/
private static File getOutputMediaFile(int type) {
// External sdcard location
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
Config.IMAGE_DIRECTORY_NAME);
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d(TAG, "Oops! Failed create "
+ Config.IMAGE_DIRECTORY_NAME + " directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
} else {
return null;
}
return mediaFile;
}
Logcat
java.lang.NullPointerException: file
at android.net.Uri.fromFile(Uri.java:447)
at com.riafy.user.imagegallerydemo.MainActivity.getOutputMediaFileUri(MainActivity.java:235)
at com.riafy.user.imagegallerydemo.MainActivity.captureImage(MainActivity.java:97)
at com.riafy.user.imagegallerydemo.MainActivity.access$100(MainActivity.java:29)
at com.riafy.user.imagegallerydemo.MainActivity$2.onClick(MainActivity.java:68)
at android.view.View.performClick(View.java:4761)
at android.view.View$PerformClick.run(View.java:19767)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5312)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
推荐答案
getOutputMediaFile(type)返回null.
getOutputMediaFile(type) returns null.
public Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
您要返回这里:
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d(TAG, "Oops! Failed create "
+ Config.IMAGE_DIRECTORY_NAME + " directory");
return null;
}
}
您添加了以下权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
出现在你的清单上?
这篇关于空指针文件URI上的异常?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
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