java.lang.NullPointerException: println needs a message
Problemi is in e.getMessage() what can return null and Log.e (String tag, String msg) will throws an new exception !!!!
Problem and solution:
LogCat:
Or you can using this code:
Problem and solution:
try {
int [] i = {1};
int z = i[5];
} catch (ArrayIndexOutOfBoundsException e) {
String s = e.toString(); // s == java.lang.ArrayIndexOutOfBoundsException
// try to testing String s for null value
if(s != null)
Log.e("bla", s);
else
Log.e("bla", "My error text 1");
String s2 = e.getMessage(); // s2 == null !!!!!!!
// you need to testing String s2 for null value , or you get FATAL EXCEPTION: main
// and application will be crashed
String s2 = e.getMessage(); // s2 == null !!!!!!!
if(s2 != null)
Log.e("bla2", e.getMessage());
else
Log.e("bla2", "My error text 2");
// this is OK
e.printStackTrace();
}
LogCat:
E/bla(855): java.lang.ArrayIndexOutOfBoundsException
E/bla2(855): My error text 2
W/System.err(855): java.lang.ArrayIndexOutOfBoundsException
W/System.err(855): at cz.okhelp.motion._MotionActivity.onTouchEvent(_MotionActivity.java:54)
W/System.err(855): at android.app.Activity.dispatchTouchEvent(Activity.java:2099)
W/System.err(855): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
W/System.err(855): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
W/System.err(855): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
W/System.err(855): at android.os.Handler.dispatchMessage(Handler.java:99)
W/System.err(855): at android.os.Looper.loop(Looper.java:123)
W/System.err(855): at android.app.ActivityThread.main(ActivityThread.java:3683)
W/System.err(855): at java.lang.reflect.Method.invokeNative(Native Method)
W/System.err(855): at java.lang.reflect.Method.invoke(Method.java:507)
W/System.err(855): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
W/System.err(855): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
W/System.err(855): at dalvik.system.NativeStart.main(Native Method)
Or you can using this code:
try {
int [] i = {1};
int z = i[5];
} catch (Exception e) {
StringBuilder sb = new StringBuilder().append(e.getClass().getSimpleName());
if (e.getMessage() != null) {
sb.append("
");
sb.append(e.getMessage());
}
Log.e("err", sb.toString()); // E/err(336): ArrayIndexOutOfBoundsException
// this code write out all message
Log.e("myError", "methodName", e);
}
// E/myError(371): methodName
// E/myError(371): java.lang.ArrayIndexOutOfBoundsException
// E/myError(371): at cz.okhelp.motion._MotionActivity.onTouchEvent(_MotionActivity.java:54)
// E/myError(371): at android.app.Activity.dispatchTouchEvent(Activity.java:2099)
// E/myError(371): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
// E/myError(371): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
// E/myError(371): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
// E/myError(371): at android.os.Handler.dispatchMessage(Handler.java:99)
// E/myError(371): at android.os.Looper.loop(Looper.java:123)
// E/myError(371): at android.app.ActivityThread.main(ActivityThread.java:3683)
// E/myError(371): at java.lang.reflect.Method.invokeNative(Native Method)
// E/myError(371): at java.lang.reflect.Method.invoke(Method.java:507)
// E/myError(371): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
// E/myError(371): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
// E/myError(371): at dalvik.system.NativeStart.main(Native Method)
396LW NO topic_id
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Další témata ....(Topics)
If you do click on Rebuid project menu item, this operation maybe consume long time on slovly PC.
Some errors dismis when you do rebuild project, or module.
Try this:
Select module where contains red error code and press Debugg or Run button on Android Studio.
If module code contains errors, Android Studio show error report in gradle console.
If not, apk will installed on device.
This is 10 times faster than Clean - Rebuild all project.
Some errors dismis when you do rebuild project, or module.
Try this:
Select module where contains red error code and press Debugg or Run button on Android Studio.
If module code contains errors, Android Studio show error report in gradle console.
If not, apk will installed on device.
This is 10 times faster than Clean - Rebuild all project.
Copy file to another
Copy and compress file
File path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File file = new File(path, "MyPicture.jpg");
// the Pictures directory exists?
path.mkdirs();
InputStream is = getResources().openRawResource(R.drawable.flower_blue);
OutputStream os = new FileOutputStream(file);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
Copy and compress file
Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
R.drawable.flower_blue);
try {
FileOutputStream out = new FileOutputStream("new_bitmap.jpg");
bitmapOrg.compress(Bitmap.CompressFormat.JPEG, 90, out);
} catch (Exception e) {
e.printStackTrace();
Log.e("saveBitmap", e.getMessage());
}
Open your workspace folder and subfolder .metadata:
C:\Users\workspace\.metadata\
Delete .lock file
C:\Users\workspace\.metadata\
Delete .lock file
Try this solutions:
1.) Save xml file
2.) Close tab with xml file
3.) Reopen xml file
1.) Open from menu Window->Android SDK Manager
2.) Select available updates (Tools, SDK etc.)
3.) Install updates
1.) Open from menu Help->Check for Updates
2.) Install available plugins what You need
3.) Restart Eclipse
1.) Save xml file
2.) Close tab with xml file
3.) Reopen xml file
1.) Open from menu Window->Android SDK Manager
2.) Select available updates (Tools, SDK etc.)
3.) Install updates
1.) Open from menu Help->Check for Updates
2.) Install available plugins what You need
3.) Restart Eclipse
StringBuilder, res/raw folder, try catch finaly throws, BufferedReader, InputStream, openRawResource, getResources Android example
MainActivity.java
MainActivity.java
public class MainActivity extends Activity {
TextView txtV;
Context cntx;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txtV = (TextView)findViewById(R.id.idLabel);
cntx = this;
try {
StringBuilder strBuilder = myFunction(cntx);
txtV.setText(strBuilder);
} catch (IOException e) {
e.printStackTrace();
}
}
private StringBuilder myFunction(Context context) throws IOException {
final Resources resources = context.getResources();
InputStream inputStream = resources.openRawResource(R.raw.my_file);
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder strBuild = new StringBuilder();
try {
String line;
while ((line = reader.readLine()) != null) {
strBuild.append(line);
}
} finally {
reader.close();
}
return strBuild;
}
}
Editace: 2013-12-09 10:21:23
Počet článků v kategorii: 396
Url:java-lang-nullpointerexception-println-needs-a-message
