我一直在关注本教程：AndroidHive - working with Camera API尝试启用我的应用中的照片。但是，一旦按下我的＆＃34;拍照按钮＆＃34;我就会收到错误。
logcat的：
09-16 11:04:00.539 19561-19561/au.gov.nsw.shellharbour.saferroadsshellharbour D/Dob_in_a_Hoon_photos﹕ Failed to create Dob_in_a_Hoon_photos directory
09-16 11:04:00.539 19561-19561/au.gov.nsw.shellharbour.saferroadsshellharbour D/AndroidRuntime﹕ Shutting down VM
09-16 11:04:00.539 19561-19561/au.gov.nsw.shellharbour.saferroadsshellharbour W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40e21438)
09-16 11:04:00.559 19561-19561/au.gov.nsw.shellharbour.saferroadsshellharbour E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException: file
at android.net.Uri.fromFile(Uri.java:441)
at au.gov.nsw.shellharbour.saferroadsshellharbour.dob_in_a_hoon.getOutputMediaFileUri(dob_in_a_hoon.java:97)
at au.gov.nsw.shellharbour.saferroadsshellharbour.dob_in_a_hoon.captureImage(dob_in_a_hoon.java:89)
at au.gov.nsw.shellharbour.saferroadsshellharbour.dob_in_a_hoon.access$000(dob_in_a_hoon.java:28)
at au.gov.nsw.shellharbour.saferroadsshellharbour.dob_in_a_hoon$1.onClick(dob_in_a_hoon.java:60)
at android.view.View.performClick(View.java:4191)
at android.view.View$PerformClick.run(View.java:17229)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4963)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
09-16 11:04:10.529 19561-19561/au.gov.nsw.shellharbour.saferroadsshellharbour I/Process﹕ Sending signal. PID: 19561 SIG: 9
这是我的.java文件：
public class dob_in_a_hoon extends ActionBarActivity {
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
public static final int MEDIA_TYPE_IMAGE = 1;
private static final String IMAGE_DIRECTORY_NAME = "Dob_in_a_Hoon_photos";
private Uri fileUri;
private ImageView Hoon_Image;
private Button button_take_photo;
private String driver_spinner_array[];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dob_in_a_hoon);
driver_spinner_array = new String[2];
driver_spinner_array[0] = "Yes";
driver_spinner_array[1] = "No";
Spinner Driver_spinner = (Spinner) findViewById(R.id.driver_selector);
ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_dropdown_item_1line, driver_spinner_array);
Driver_spinner.setAdapter(adapter);
Hoon_Image = (ImageView) findViewById(R.id.CapturedImage);
button_take_photo = (Button)findViewById(R.id.btn_take_photo);
button_take_photo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
captureImage();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.dob_in_a_hoon, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private void captureImage(){
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
}
public Uri getOutputMediaFileUri(int type){
return Uri.fromFile(getOutputMediaFile(type));
}
private static File getOutputMediaFile(int type){
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),IMAGE_DIRECTORY_NAME);
if (!mediaStorageDir.exists()){
if (!mediaStorageDir.mkdirs()){
Log.d(IMAGE_DIRECTORY_NAME, "Failed to create " + IMAGE_DIRECTORY_NAME + " directory");
return null;
}
}
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;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE){
if (resultCode==RESULT_OK){
previewCapturedImage();
}else if (resultCode == RESULT_CANCELED){
Toast.makeText(getApplicationContext(),"User Cancelled image Capture", Toast.LENGTH_SHORT).show();
}else {
Toast.makeText(getApplicationContext(),"Failed to capture image", Toast.LENGTH_SHORT).show();
}
}
}
private void previewCapturedImage(){
try{
Hoon_Image.setVisibility(View.VISIBLE);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(),options);
Hoon_Image.setImageBitmap(bitmap);
}catch (NullPointerException e){
e.printStackTrace();
}
}
@Override
protected void onSaveInstanceState(Bundle outState){
super .onSaveInstanceState(outState);
outState.putParcelable("file_uri", fileUri);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState){
super.onRestoreInstanceState(savedInstanceState);
fileUri = savedInstanceState.getParcelable("file_uri");
}
}
任何人都可以在我的代码中看到我出错的地方，以及我需要做些什么来修复它？
答案 0 :(得分：1)
我创建了一个示例代码段并测试了代码中显示的mkdirs，如果我删除了权限，它会导致类似的异常
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
您能检查一下您的清单，以确保您已定义这些清单。
如果以上不是问题，另一个（不太可能的）错误来源可能是您的SD卡空间不足或某些权限限制。在这种情况下，我会在Android模拟器或其他设备上尝试应用程序。
答案 1 :(得分：1)
这应该在Manifest中添加以使用相机功能：
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:glEsVersion="0x00020000"
android:required="true"/>