android-文件-URI上存在空指针异常
我是android开发新手。我有一个按钮,可以在点击时捕获图像。单击按钮时,它会抛出空指针异常错误 这是我的主要活动方法android-文件-URI上存在空指针异常,android,nullpointerexception,android-camera,android-manifest,Android,Nullpointerexception,Android Camera,Android Manifest,我是android开发新手。我有一个按钮,可以在点击时捕获图像。单击按钮时,它会抛出空指针异常错误 这是我的主要活动方法 btnCapturePicture.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { captureImage(); } }); /** Record video button cl
btnCapturePicture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
captureImage();
}
});
/**
Record video button click event
*/
btnRecordVideo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// record video
recordVideo();
}
});
// Checking camera availability
if (!isDeviceSupportCamera()) {
Toast.makeText(getApplicationContext(),
"Sorry! Your device doesn't support camera",
Toast.LENGTH_LONG).show();
// will close the app if the device does't have camera
finish();
}
}
/**
checking device has camera hardware or not
*/
private boolean isDeviceSupportCamera() {
if (getApplicationContext().getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/**
* Launching camera app to capture image
*/
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_CAPTURE_IMAGE_REQUEST_CODE);
}
/**
* Launching camera app to record video
*/
private void recordVideo() {
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);
// set video quality
intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);// set the image file
// name
// start the video capture Intent
startActivityForResult(intent, CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
}
/**
* Here we store the file url as it will be null after returning from camera
* app
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// save file url in bundle as it will be null on screen orientation
// changes
outState.putParcelable("file_uri", fileUri);
}
@Override
protected void onRestoreInstanceState (Bundle savedInstanceState){
super.onRestoreInstanceState(savedInstanceState);
// get the file url
fileUri = savedInstanceState.getParcelable("file_uri");
}
/**
* Receiving activity result method will be called after closing the camera
* */
@Override
protected void onActivityResult ( int requestCode, int resultCode, Intent data){
// if the result is capturing Image
if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// successfully captured the image
// launching upload activity
launchUploadActivity(true);
} else if (resultCode == RESULT_CANCELED) {
// user cancelled Image capture
Toast.makeText(getApplicationContext(),
"Sorry! Failed to capture image", Toast.LENGTH_SHORT).show();
}
} else if (requestCode == CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// video successfully recorded
//launching upload activity
launchUploadActivity(false);
} else if (resultCode == RESULT_CANCELED) {
// user cancelled recording
Toast.makeText(getApplicationContext(), "Sorry! Failed to record video", Toast.LENGTH_SHORT).show();
}
}
}
private void launchUploadActivity(boolean isImage){
Intent i = new Intent(MainActivity.this, UploadActivity.class);
i.putExtra("filePath", fileUri.getPath());
i.putExtra("isImage", isImage);
startActivity(i);
}
/**
* Creating file uri to store image/video
*/
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 if (type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator+ "VID_" + timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
}
我在清单文件中添加了创建目录的权限,这是我的manifest.xml文件
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="11"
android:targetSdkVersion="23" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
我执行了你的代码,它正在拍照并存储。您可能缺少权限,请进入“设置”>“应用”>“应用”>“并检查权限”。还要检查“mediaStorageDir”和“mediaFile”是否不为空。将一些日志放在那里。从清单上看,您似乎没有使用
我发现Intent Intent=新意图(MediaStore.ACTION\u IMAGE\u CAPTURE)代码>
在你的代码中 请尝试此功能:
private void captureImage(){
Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
/* create instance of File with name img.jpg */
File file = new File(Environment.getExternalStorageDirectory() + File.separator + "img.jpg");
/* put uri as extra in intent object */
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
intent.putExtra(MediaStore.EXTRA_SCREEN_ORIENTATION, ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
startActivityForResult(intent, 1);
}
看起来像getOutputMediaFile(int类型)
返回null
。使用调试器找出whyreturn Uri.fromFile(getOutputMediaFile(type));这应该是一个评论…它起作用了…编辑你的答案…我会更新我不能发表评论。至少需要50个声誉。谢谢@Rotwang:)在清单文件中添加了摄像头权限。仍然抛出相同的错误尝试此函数,仍然相同的错误添加此权限添加那些权限,仍然没有运气
private void captureImage(){
Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
/* create instance of File with name img.jpg */
File file = new File(Environment.getExternalStorageDirectory() + File.separator + "img.jpg");
/* put uri as extra in intent object */
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
intent.putExtra(MediaStore.EXTRA_SCREEN_ORIENTATION, ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
startActivityForResult(intent, 1);
}