Question

android的界面怎么只占屏幕的一半

Answer 1

android弹出一个占屏幕一半的菜单，可以使用popupwindow，设置弹出的xy轴的距离占据屏幕一半即可，如下代码：

package com.example.hellopopupwindow;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.PopupWindow;
import android.widget.Toast;

public class MainActivity extends Activity {

private Context mContext = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

mContext = this;

Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View view) {

showPopupWindow(view);
}
});
}

private void showPopupWindow(View view) {

// 一个自定义的布局，作为显示的内容
View contentView = LayoutInflater.from(mContext).inflate(
R.layout.pop_window, null);
// 设置按钮的点击事件
Button button = (Button) contentView.findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
Toast.makeText(mContext, "button is pressed",
Toast.LENGTH_SHORT).show();
}
});

final PopupWindow popupWindow = new PopupWindow(contentView,
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, true);

popupWindow.setTouchable(true);

popupWindow.setTouchInterceptor(new OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {

Log.i("mengdd", "onTouch : ");

return false;
// 这里如果返回true的话，touch事件将被拦截
// 拦截后 PopupWindow的onTouchEvent不被调用，这样点击外部区域无法dismiss
}
});

// 如果不设置PopupWindow的背景，无论是点击外部区域还是Back键都无法dismiss弹框
// 我觉得这里是API的一个bug
popupWindow.setBackgroundDrawable(getResources().getDrawable(
R.drawable.selectmenu_bg_downward));

// 设置好参数之后再show
popupWindow.showAsDropDown(view);

}

}