Android - 可移动/可拖动的浮动操作按钮 (FAB)

Question

我在我的应用程序中使用 FloatingActionButton 。有时，它会与基本内容重叠，所以我想这样做，以便用户可以将 FAB 拖到一边。

本身不需要拖放功能。它只需要是可移动的。文档没有提到这一点，但我确信我在其他应用程序中看到过这样的功能。

您能建议/提供有关如何执行此操作的代码片段（最好是 XML 格式）。

原文由 ban-geoengineering 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

基于 this answer for another SO question 这是我创建的代码。它似乎工作得很好（具有工作点击功能）并且不依赖于 FAB 的父布局或定位……

 package com.example;

import android.content.Context;
import android.support.design.widget.FloatingActionButton;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;

public class MovableFloatingActionButton extends FloatingActionButton implements View.OnTouchListener {

    private final static float CLICK_DRAG_TOLERANCE = 10; // Often, there will be a slight, unintentional, drag when the user taps the FAB, so we need to account for this.

    private float downRawX, downRawY;
    private float dX, dY;

    public MovableFloatingActionButton(Context context) {
        super(context);
        init();
    }

    public MovableFloatingActionButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MovableFloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent){

        ViewGroup.MarginLayoutParams layoutParams = (ViewGroup.MarginLayoutParams)view.getLayoutParams();

        int action = motionEvent.getAction();
        if (action == MotionEvent.ACTION_DOWN) {

            downRawX = motionEvent.getRawX();
            downRawY = motionEvent.getRawY();
            dX = view.getX() - downRawX;
            dY = view.getY() - downRawY;

            return true; // Consumed

        }
        else if (action == MotionEvent.ACTION_MOVE) {

            int viewWidth = view.getWidth();
            int viewHeight = view.getHeight();

            View viewParent = (View)view.getParent();
            int parentWidth = viewParent.getWidth();
            int parentHeight = viewParent.getHeight();

            float newX = motionEvent.getRawX() + dX;
            newX = Math.max(layoutParams.leftMargin, newX); // Don't allow the FAB past the left hand side of the parent
            newX = Math.min(parentWidth - viewWidth - layoutParams.rightMargin, newX); // Don't allow the FAB past the right hand side of the parent

            float newY = motionEvent.getRawY() + dY;
            newY = Math.max(layoutParams.topMargin, newY); // Don't allow the FAB past the top of the parent
            newY = Math.min(parentHeight - viewHeight - layoutParams.bottomMargin, newY); // Don't allow the FAB past the bottom of the parent

            view.animate()
                    .x(newX)
                    .y(newY)
                    .setDuration(0)
                    .start();

            return true; // Consumed

        }
        else if (action == MotionEvent.ACTION_UP) {

            float upRawX = motionEvent.getRawX();
            float upRawY = motionEvent.getRawY();

            float upDX = upRawX - downRawX;
            float upDY = upRawY - downRawY;

            if (Math.abs(upDX) < CLICK_DRAG_TOLERANCE && Math.abs(upDY) < CLICK_DRAG_TOLERANCE) { // A click
                return performClick();
            }
            else { // A drag
                return true; // Consumed
            }

        }
        else {
            return super.onTouchEvent(motionEvent);
        }

    }

}

这是 XML…

     <com.example.MovableFloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@drawable/ic_navigate_next_white_24dp"/>

基本上，您只需要在 XML 中将 android.support.design.widget.FloatingActionButton com.example.MovableFloatingActionButton 。

原文由 ban-geoengineering 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

试试这个：

 public class MainActivity extends AppCompatActivity implements View.OnTouchListener {
  float dX;
  float dY;
  int lastAction;

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

    final View dragView = findViewById(R.id.draggable_view);
    dragView.setOnTouchListener(this);
  }

  @Override
  public boolean onTouch(View view, MotionEvent event) {
    switch (event.getActionMasked()) {
      case MotionEvent.ACTION_DOWN:
        dX = view.getX() - event.getRawX();
        dY = view.getY() - event.getRawY();
        lastAction = MotionEvent.ACTION_DOWN;
        break;

      case MotionEvent.ACTION_MOVE:
        view.setY(event.getRawY() + dY);
        view.setX(event.getRawX() + dX);
        lastAction = MotionEvent.ACTION_MOVE;
        break;

      case MotionEvent.ACTION_UP:
        if (lastAction == MotionEvent.ACTION_DOWN)
          Toast.makeText(DraggableView.this, "Clicked!", Toast.LENGTH_SHORT).show();
        break;

      default:
        return false;
    }
    return true;
  }
}

和 XML：

 <ImageButton
        android:id="@+id/draggable_view"
        android:background="@mipmap/ic_launcher"
        android:layout_gravity="bottom|right"
        android:layout_marginBottom="20dp"
        android:layout_marginEnd="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

您可以使任何视图可拖动和可点击。

原文由 Akanshi Srivastava 发布，翻译遵循 CC BY-SA 4.0 许可协议