为什么不出现FloatingActionButton？(Why does not appear FloatingActionButton?)

 我将我的问题改为更易于理解的问题。 但现在又出现了另一个问题。 为什么不出现FloatingActionButton 
 
 为什么不出现FloatingActionButton为什么不出现FloatingActionButton 
 
 
public class Home extends MyAppCompact 
{
   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home); //This is problem
    }

}
 
 // 
 
public class MyAppCompact extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LinearLayout.LayoutParams layoutParams=new LinearLayout.
                LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        FloatingActionButton floatingActionButton=new FloatingActionButton(this);
        layoutParams.gravity= Gravity.BOTTOM|Gravity.RIGHT;
        layoutParams.setMargins(16,16,16,16);

        floatingActionButton.setLayoutParams(layoutParams);
        floatingActionButton.setImageResource(R.drawable.ic_mic_white_24dp);
        floatingActionButton.setClickable(true);

        floatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                Bitmap bitmap=getScreenShot();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
                byte[] byteArray = stream.toByteArray();

                Intent intent = new Intent(MyAppCompact.this, FeedBack.class);
                intent.putExtra("bitmapData", byteArray);
                startActivity(intent);
            }
        });

        LinearLayout.LayoutParams layoutParams1=new LinearLayout.
                LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT
        );

        addContentView(floatingActionButton,layoutParams1);

        //
//            <android.support.design.widget.FloatingActionButton
//        android:layout_width="wrap_content"
//        android:layout_height="wrap_content"
//        android:layout_gravity="bottom|right"
//        android:layout_margin="16dp"
//        android:id="@+id/btnFloating"
//        android:clickable="true"
//        android:src="@drawable/ic_mic_white_24dp" />
    }

    public Bitmap getScreenShot() {
        View rootView = getWindow().getDecorView().findViewById(android.R.id.content);
        View screenView = rootView.getRootView();
        screenView.setDrawingCacheEnabled(true);
        Bitmap bitmap = Bitmap.createBitmap(screenView.getDrawingCache());
        screenView.setDrawingCacheEnabled(false);
        return bitmap;
    }
}

I changed my question to a more understandable one. But now there was another problem. Why does not appear FloatingActionButton
 
Why does not appear FloatingActionButton Why does not appear FloatingActionButton
 
 
public class Home extends MyAppCompact 
{
   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home); //This is problem
    }

}
 
//
 
public class MyAppCompact extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LinearLayout.LayoutParams layoutParams=new LinearLayout.
                LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        FloatingActionButton floatingActionButton=new FloatingActionButton(this);
        layoutParams.gravity= Gravity.BOTTOM|Gravity.RIGHT;
        layoutParams.setMargins(16,16,16,16);

        floatingActionButton.setLayoutParams(layoutParams);
        floatingActionButton.setImageResource(R.drawable.ic_mic_white_24dp);
        floatingActionButton.setClickable(true);

        floatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                Bitmap bitmap=getScreenShot();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
                byte[] byteArray = stream.toByteArray();

                Intent intent = new Intent(MyAppCompact.this, FeedBack.class);
                intent.putExtra("bitmapData", byteArray);
                startActivity(intent);
            }
        });

        LinearLayout.LayoutParams layoutParams1=new LinearLayout.
                LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT
        );

        addContentView(floatingActionButton,layoutParams1);

        //
//            <android.support.design.widget.FloatingActionButton
//        android:layout_width="wrap_content"
//        android:layout_height="wrap_content"
//        android:layout_gravity="bottom|right"
//        android:layout_margin="16dp"
//        android:id="@+id/btnFloating"
//        android:clickable="true"
//        android:src="@drawable/ic_mic_white_24dp" />
    }

    public Bitmap getScreenShot() {
        View rootView = getWindow().getDecorView().findViewById(android.R.id.content);
        View screenView = rootView.getRootView();
        screenView.setDrawingCacheEnabled(true);
        Bitmap bitmap = Bitmap.createBitmap(screenView.getDrawingCache());
        screenView.setDrawingCacheEnabled(false);
        return bitmap;
    }
}

原文：https://stackoverflow.com/questions/43013819