এমন কোনও সময় আছে যখন আপনার কোনও ক্রিয়াকলাপের অনক্রিট থাকা অবস্থায় কোনও বিন্যাসের জন্য উপলভ্য জায়গার সুনির্দিষ্ট মাত্রাগুলি জানতে হবে। কিছু চিন্তা করার পরে আমি এটি করার এই পদ্ধতিতে কাজ করেছি।
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
startActivityForResult(new Intent(this, Measure.class), 1);
// Return without setting the layout, that will be done in onActivityResult.
}
@Override
protected void onActivityResult (int requestCode, int resultCode, Intent data) {
// Probably can never happen, but just in case.
if (resultCode == RESULT_CANCELED) {
finish();
return;
}
int width = data.getIntExtra("Width", -1);
// Width is now set to the precise available width, and a layout can now be created. ...
}
}
public final class Measure extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Create a LinearLayout with a MeasureFrameLayout in it.
// Just putting a subclass of LinearLayout in works fine, but to future proof things, I do it this way.
LinearLayout linearLayout = new LinearLayout(this);
LinearLayout.LayoutParams matchParent = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
MeasureFrameLayout measureFrameLayout = new MeasureFrameLayout(this);
measureFrameLayout.setLayoutParams(matchParent);
linearLayout.addView(measureFrameLayout);
this.addContentView(linearLayout, matchParent);
// measureFrameLayout will now request this second activity to finish, sending back the width.
}
class MeasureFrameLayout extends FrameLayout {
boolean finished = false;
public MeasureFrameLayout(Context context) {
super(context);
}
@SuppressLint("DrawAllocation")
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (finished) {
return;
}
finished = true;
// Send the width back as the result.
Intent data = new Intent().putExtra("Width", MeasureSpec.getSize(widthMeasureSpec));
Measure.this.setResult(Activity.RESULT_OK, data);
// Tell this activity to finish, so the result is passed back.
Measure.this.finish();
}
}
}
যদি কোনও কারণে আপনি অ্যান্ড্রয়েড ম্যানিফেস্টে অন্য ক্রিয়াকলাপ যোগ করতে না চান তবে আপনি এটি এইভাবে করতে পারেন:
public class MainActivity extends Activity {
static Activity measuringActivity;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Bundle extras = getIntent().getExtras();
if (extras == null) {
extras = new Bundle();
}
int width = extras.getInt("Width", -2);
if (width == -2) {
// First time in, just start another copy of this activity.
extras.putInt("Width", -1);
startActivityForResult(new Intent(this, MainActivity.class).putExtras(extras), 1);
// Return without setting the layout, that will be done in onActivityResult.
return;
}
if (width == -1) {
// Second time in, here is where the measurement takes place.
// Create a LinearLayout with a MeasureFrameLayout in it.
// Just putting a subclass of LinearLayout in works fine, but to future proof things, I do it this way.
LinearLayout linearLayout = new LinearLayout(measuringActivity = this);
LinearLayout.LayoutParams matchParent = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
MeasureFrameLayout measureFrameLayout = new MeasureFrameLayout(this);
measureFrameLayout.setLayoutParams(matchParent);
linearLayout.addView(measureFrameLayout);
this.addContentView(linearLayout, matchParent);
// measureFrameLayout will now request this second activity to finish, sending back the width.
}
}
@Override
protected void onActivityResult (int requestCode, int resultCode, Intent data) {
// Probably can never happen, but just in case.
if (resultCode == RESULT_CANCELED) {
finish();
return;
}
int width = data.getIntExtra("Width", -3);
// Width is now set to the precise available width, and a layout can now be created.
...
}
class MeasureFrameLayout extends FrameLayout {
boolean finished = false;
public MeasureFrameLayout(Context context) {
super(context);
}
@SuppressLint("DrawAllocation")
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (finished) {
return;
}
finished = true;
// Send the width back as the result.
Intent data = new Intent().putExtra("Width", MeasureSpec.getSize(widthMeasureSpec));
MainActivity.measuringActivity.setResult(Activity.RESULT_OK, data);
// Tell the (second) activity to finish.
MainActivity.measuringActivity.finish();
}
}