Android移動視圖觸摸事件

Question

我想在我的布局中移動兩個不同的視圖，以便用戶可以像他的願望一樣顯示它。

到目前為止，我已經制作了以下代碼來處理觸摸事件：

this.viewEvent.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View view, MotionEvent event)
    {           
        final int y = (int) event.getRawY();

        RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) view.getLayoutParams();
        switch (event.getAction() & MotionEvent.ACTION_MASK)
        {
            case MotionEvent.ACTION_DOWN:
                element.setEventY(y - params.topMargin);
                break;

            case MotionEvent.ACTION_UP:
                viewGroup.invalidate();
                break;

            case MotionEvent.ACTION_POINTER_DOWN:
            case MotionEvent.ACTION_POINTER_UP:
                break;

            case MotionEvent.ACTION_MOVE:
                params.topMargin = y - element.getEventY();
                params.bottomMargin = screenHeight - view.getHeight() - params.topMargin;

                // Avoid out of screen
                if (params.topMargin < 0) return true;

                // Apply changes
                view.setLayoutParams(params);
                break;
        }

        return true;
    }
});

element是處理位置的自定義對象的實例。 screenHeight是Display類給出的屏幕高度。

我能夠移動元素，但是當我觸摸它時它會閃爍，一旦我把手指放上，視圖就會消失。 我甚至無法檢索它，它只是在屏幕外。

我做錯了什么？

謝謝你的幫助

Answer 1

使用以下代碼執行簡單的Touch to move ：

layout_counter.setOnTouchListener(new OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent event)
        {
            if (currentState != State.EDIT_MOVE) return false;

            FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) view.getLayoutParams();
            if (view.getId() != R.id.layout_counter) return false;

            switch (event.getAction())
            {
                case MotionEvent.ACTION_MOVE:
                    params.topMargin = (int) event.getRawY() - view.getHeight();
                    params.leftMargin = (int) event.getRawX() - (view.getWidth() / 2);
                    view.setLayoutParams(params);
                    break;

                case MotionEvent.ACTION_UP:
                    params.topMargin = (int) event.getRawY() - view.getHeight();
                    params.leftMargin = (int) event.getRawX() - (view.getWidth() / 2);
                    view.setLayoutParams(params);
                    break;

                case MotionEvent.ACTION_DOWN:
                    view.setLayoutParams(params);
                    break;
            }

            return true;
        }
    });

layout_counter是您要移動的視圖。

不要忘記將可移動元素放入FrameLayout

Answer 2

我創建了移動視圖的庫：

• 對於低於JellyBean（16）的API，它會在其父容器中修改視圖的邊距
• 對於API JellyBean及更高版本，它修改其父容器中的絕對視圖位置

只需添加依賴項：

dependencies {
    compile 'com.scalified:viewmover:1.1.0'
}

您可以在GitHub上找到更多信息

Answer 3

我將為那些使用相對布局的人提供替代解決方案。

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewTreeObserver;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends Activity implements View.OnTouchListener
{
    private int       _xDelta;
    private int       _yDelta;
    private int       _rightMargin;
    private int       _bottomMargin;
    private ImageView _floatingView;

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

        this._floatingView = (ImageView) findViewById(R.id.textView);

        this._floatingView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener()
        {
            @Override
            public boolean onPreDraw()
            {
                if (_floatingView.getViewTreeObserver().isAlive())
                    _floatingView.getViewTreeObserver().removeOnPreDrawListener(this);

                updateLayoutParams(_floatingView);
                return false;
            }
        });

        this._floatingView.setOnTouchListener(this);
    }

    private void updateLayoutParams(View view)
    {
        this._rightMargin = -view.getMeasuredWidth();
        this._bottomMargin = -view.getMeasuredHeight();

        RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(view.getMeasuredWidth(), view.getMeasuredHeight());
        layoutParams.bottomMargin = this._bottomMargin;
        layoutParams.rightMargin = this._rightMargin;

        view.setLayoutParams(layoutParams);
    }

    @Override
    public boolean onTouch(View view, MotionEvent event)
    {
        if (view == this._floatingView)
        {
            final int X = (int) event.getRawX();
            final int Y = (int) event.getRawY();

            switch (event.getAction() & MotionEvent.ACTION_MASK)
            {
                case MotionEvent.ACTION_DOWN:
                    RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
                    this._xDelta = X - lParams.leftMargin;
                    this._yDelta = Y - lParams.topMargin;
                    break;

                case MotionEvent.ACTION_MOVE:
                    RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
                    layoutParams.leftMargin = X - this._xDelta;
                    layoutParams.topMargin = Y - this._yDelta;
                    layoutParams.rightMargin = this._rightMargin;
                    layoutParams.bottomMargin = this._bottomMargin;
                    view.setLayoutParams(layoutParams);
                    break;
            }

            return true;
        }
        else
        {
            return false;
        }
    }
}