Android PopupWindow

代码：

package zhangphil.test;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.PopupWindow;
import android.widget.TextView;

public class TestActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test_activity);
        Button mButton = findViewById(R.id.button);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                show(mButton, 0, 0);
            }
        });
    }

    private void show(View view, int xOff, int yOff) {
        View contentView = LayoutInflater.from(getApplicationContext()).inflate(android.R.layout.simple_list_item_2, null, false);
        contentView.setBackgroundColor(Color.LTGRAY);

        TextView text1 = contentView.findViewById(android.R.id.text1);
        text1.setText("zhang");

        TextView text2 = contentView.findViewById(android.R.id.text2);
        text2.setText("phil");

        float[] size = getDeviceDisplaySize(getApplicationContext());
        PopupWindow window = new PopupWindow(contentView, (int) size[0], 300, true);
        //window.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

        window.setOutsideTouchable(true);
        window.setTouchable(true);

        window.showAsDropDown(view, xOff, yOff);
    }

    public static float[] getDeviceDisplaySize(Context context) {
        Resources resources = context.getResources();
        DisplayMetrics dm = resources.getDisplayMetrics();
        int width = dm.widthPixels;
        int height = dm.heightPixels;

        float[] size = new float[2];
        size[0] = width;
        size[1] = height;

        return size;
    }
}

运行如图：