安卓可移动悬浮按钮

结果图

自定义悬浮按钮

public class DraggingButton extends AppCompatButton {

    private int lastX = 0;
    private int lastY = 0;
    private int beginX = 0;
    private int beginY = 0;

    private  int screenWidth = 720;
    private  int screenHeight = 1280;


    public DraggingButton(Context context) {
        this(context, null);
    }

    public DraggingButton(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public DraggingButton(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        initData(context);
    }

    private void initData(Context context){
        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics dm = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(dm);
        screenWidth = dm.widthPixels;
        screenHeight = dm.heightPixels;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event)
    {

        switch (event.getAction())
        {
            case MotionEvent.ACTION_DOWN:
                lastX = (int) event.getRawX();      // 触摸点与屏幕左边的距离
                lastY = (int) event.getRawY();      // 触摸点与屏幕上边的距离
                beginX = lastX;
                beginY = lastY;
                break;
            case MotionEvent.ACTION_MOVE:

                int dx =(int)event.getRawX() - lastX;       // x轴拖动的绝对距离
                int dy =(int)event.getRawY() - lastY;       // y轴拖动的绝对距离

                // getLeft(): 子View的左边界到父View的左边界的距离, getRight():子View的右边界到父View的左边界的距离
                // 如下几个数据表示view应该在布局中的位置
                int left = getLeft() + dx;
                int top = getTop() + dy;
                int right = getRight() + dx;
                int bottom = getBottom() + dy;
                if(left < 0){
                    left = 0;
                    right = left + getWidth();
                }
                if(right > screenWidth){
                    right = screenWidth;
                    left = right - getWidth();
                }
                if(top < 0){
                    top = 0;
                    bottom = top + getHeight();
                }
                if(bottom>screenHeight){
                    bottom = screenHeight;
                    top = bottom - getHeight();
                }
                layout(left, top, right, bottom);
                lastX = (int) event.getRawX();
                lastY = (int) event.getRawY();
                break;
            case MotionEvent.ACTION_UP:
                // 解决拖拽的时候松手点击事件触发
                if (Math.abs(lastX - beginX) < 10 && Math.abs(lastY - beginY) < 10){
                    return super.onTouchEvent(event);
                }else{
                    setPressed(false);
                    return true;
                }
            default:
                break;
        }
        return super.onTouchEvent(event);
    }
}

主活动

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <com.coolweather.fuelconsumption.DraggingButton
        android:id="@+id/tv_dragging"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_gravity="right"
        android:layout_margin="20dp"
        android:background="@drawable/drag_button_bg"
        android:gravity="center"
        android:padding="10dp"
        android:text="悬浮\n按钮1"
        android:textColor="#ffffff"
        android:textSize="15sp" />


</androidx.coordinatorlayout.widget.CoordinatorLayout>

按钮样式drag_button_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true">
        <shape android:shape="oval">
            <!--填充颜色-->
            <solid android:color="#bf39b500" />
            <!--描边-->
            <stroke android:width="2dp" android:color="#bf39b500" />
        </shape>
    </item>
    <item>
        <shape android:shape="oval">
            <!--填充颜色-->
            <solid android:color="#ff8bc34a" />
            <!--描边-->
            <stroke android:width="2dp" android:color="#bf39b500"/>
        </shape>
    </item>
</selector>

主活动中调用

    private DraggingButton mDraggintView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDraggintView = (DraggingButton) findViewById(R.id.tv_dragging);
        mDraggintView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "click", Toast.LENGTH_SHORT).show();
            }
        });
    }