获取 WindowManager

mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);

初始化 Params

mLayoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,

WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_PHONE,

WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, PixelFormat.TRANSLUCENT);

设置 Params 的其他属性

// Set gravity.

mLayoutParams.gravity = Gravity.TOP | Gravity.START;

// Adjust origin position by base point.

mLayoutParams.x = 0;

mLayoutParams.y = 0;

// Adjust origin position by margin.

mLayoutParams.verticalMargin = LAYOUT_PARAMS_VERTICAL_MARGIN;

mLayoutParams.horizontalMargin = LAYOUT_PARAMS_HORIZONTAL_MARGIN;

// Set layout height with constant.

mLayoutParams.height = LAYOUT_PARAMS_HEIGHT;

// The scale is decided by origin icon scale.

mLayoutParams.width = LAYOUT_PARAMS_HEIGHT * LAYOUT_PARAMS_SCALE;

实例化 View

mFloatingView = new ImageView(context);

mFloatingView.setImageResource(iconResId);

mFloatingView.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

// Your code here.

}

});

显示悬浮窗口

mWindowManager.addView(mFloatingView, mLayoutParams);

消除悬浮窗口

if (mFloatingView != null && mFloatingView.isShown()) {

mWindowManager.removeView(mFloatingView);

}

完整代码

/**

* Created by YuYi App Dev on 2016/8/22.

* To create a floating button.

*/

public class FloatingBackButton {

private Context context;

private int iconResId;

private Class> cls;

private ImageView mFloatingView;

private WindowManager mWindowManager;

private WindowManager.LayoutParams mLayoutParams;

/**

* Constructor function.

*

* @param context the context

* @param iconResId the pic needed to be displayed

* @param cls the class needed to be loaded when button pressed

*/

public FloatingBackButton(Context context, int iconResId, Class> cls) {

this.context = context;

this.iconResId = iconResId;

this.cls = cls;

initResources();

}

private void initResources() {

// Set as local var to save res.

final int LAYOUT_PARAMS_HEIGHT = 120;

final int LAYOUT_PARAMS_SCALE = 2;

final int LAYOUT_PARAMS_VERTICAL_MARGIN = 0;

final int LAYOUT_PARAMS_HORIZONTAL_MARGIN = 0;

mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);

mLayoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,

WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_PHONE,

WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, PixelFormat.TRANSLUCENT);

// Set gravity.

mLayoutParams.gravity = Gravity.TOP | Gravity.START;

// Adjust origin position by base point.

mLayoutParams.x = 0;

mLayoutParams.y = 0;

// Adjust origin position by margin.

mLayoutParams.verticalMargin = LAYOUT_PARAMS_VERTICAL_MARGIN;

mLayoutParams.horizontalMargin = LAYOUT_PARAMS_HORIZONTAL_MARGIN;

// Set layout height with constant.

mLayoutParams.height = LAYOUT_PARAMS_HEIGHT;

// The scale is decided by origin icon scale.

mLayoutParams.width = LAYOUT_PARAMS_HEIGHT * LAYOUT_PARAMS_SCALE;

// Must initiating when attaching, or will cause crash.

mFloatingView = new ImageView(context);

mFloatingView.setImageResource(iconResId);

mFloatingView.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

Intent intent = new Intent(context, cls);

context.startActivity(intent);

if (mFloatingView != null && mFloatingView.isShown()) {

mWindowManager.removeView(mFloatingView);

}

}

});

}

public void show() {

mWindowManager.addView(mFloatingView, mLayoutParams);

}

}