Android：移开手指时选择最近的按钮

Question

我的 activity_main 上的 LinearLayout 中有多个按钮，并且想要检测哪个 Button 最接近用户手指。当用户以一个手势移动他的手指时，最近的按钮应该突出显示，当他移开手指时，最近的按钮应该执行其 onClick 功能。

它应该像 android 或 iphone 计算器上的默认键盘一样。它选择离手指最近的按钮。当您拖动手指时，它会将选择更改为最近的键，并且只有当您松开手指时，它才会执行 onClick 功能。

引用Get button coordinates and detect if finger is over them - Android 我已经到了选择有效的地步，但前提是我点击了任何不是按钮的地方，并且当不在按钮上方时选择最近的按钮不起作用。

（在重要的情况下为 API 21 编程）

activity_main.xml

<TextView/>
<ButtonLayout>
    <LinearLayout1>
        <Button1/>
        <Space/>
        <Button2/>
        <Space/>
        <Button3/>
        <Space/>
        <Button4/>
    </LinearLayout1>
    <LinearLayout2>
        <Button5/>
        <Space/>
        <Button6/>
        <Space/>
        <Button7/>
        <Space/>
        <Button8/>
    </LinearLayout2>
</OuterLinearLayout>

Java

private View.OnTouchListener buttonLayoutTouchListener= new View.OnTouchListener(){

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

        int x = (int) event.getX();
        int y = (int) event.getY();


        //OuterLayout
        for (int i = 0; i < buttonLayout.getChildCount(); i++) {
            View inner = buttonLayout.getChildAt(i);
            //Inner
            if(inner instanceof LinearLayout) {

                for (int j = 0;j<((LinearLayout) inner).getChildCount();j++) {
                    View current = ((LinearLayout) inner).getChildAt(j);
                    if (current instanceof Button) {
                        Button b = (Button) current;
                        Rect rect = new Rect();
                        b.getGlobalVisibleRect(rect);
                        //factors for textview
                        rect.top-=300;
                        rect.bottom-=300;

                        if (!isPointWithin(x, y, rect.left, rect.right, rect.top,
                                rect.bottom)) {
                            b.getBackground().setState(defaultStates);
                        }

                        if (isPointWithin(x, y, rect.left, rect.right, rect.top,
                                rect.bottom)) {
                            if (b != mLastButton) {
                                mLastButton = b;
                                b.getBackground().setState(STATE_PRESSED);
                                //highlight button finger currently over
                           Log.d("button",mLastButton.getText().toString());
                            }
                        }

                    }
                }
            }
        }
        return true;
    }

};

static boolean isPointWithin(int x, int y, int x1, int x2, int y1, int y2) {
    return (x <= x2 && x >= x1 && y <= y2 && y >= y1);
}

Answer 1

创建一个新类来扩展 LinearLayout 并覆盖 onInterceptTouchEvent。将您的外部 LinearLayout 设置为新类。

警告：如果您只是点击一个按钮（一次在父项上，一次在子项上），这会产生两次调用 onClick 的副作用。这是我的超级肮脏的解决方法。请考虑找到真正的解决方法并发布回复。

双击解决方法

//call if(doubleClick()) in buttons' onClicklistener
public mLastClickTime=0;
public boolean doubleClick() {
    //29 is arbitrary
    if (SystemClock.elapsedRealtime() - mLastClickTime < 29) {
        return true;
    }
    mLastClickTime = SystemClock.elapsedRealtime();
    return false;
}

扩展线性布局

import android.content.Context;
import android.graphics.Rect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

public class ButtonLayout extends LinearLayout {

    public int layoutTop;

    public ButtonLayout(Context context) {
        super(context);
    }

    public ButtonLayout(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

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

    public ButtonLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Rect rect = new Rect();
        this.getGlobalVisibleRect(rect);
        layoutTop =rect.top;
        super.onSizeChanged(w, h, oldw, oldh);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        Button keep=null;

        int x = (int) ev.getX();
        int y = (int) ev.getY();

        int count = 0;
        //number of buttons
        int buttonMax =0;
        int distance = Integer.MAX_VALUE;

        //Outer LinearLayout
        outerLoop:
        for (int i = 0; i < this.getChildCount(); i++) {
            View inner = this.getChildAt(i);
            if (inner instanceof LinearLayout) {
                //Inner LinearLayout
                for (int j = 0; j < ((LinearLayout) inner).getChildCount(); j++) {
                    View current = ((LinearLayout) inner).getChildAt(j);
                    if (current instanceof Button) {
                        buttonMax++;
                        Button b = (Button) current;
                        Rect rect = new Rect();
                        b.getGlobalVisibleRect(rect);
                        rect.top -= layoutTop;
                        rect.bottom -= layoutTop;

                        //finger in button
                        if (isPointWithin(x, y, rect.left, rect.right, rect.top,
                                rect.bottom)) {
                            b.setPressed(true);
                            keep=b;
                            break outerLoop;
                        }else{
                            b.setPressed(false);
                            count++;

                            int buttonDistance = distance(x, y, rect.left, rect.right, rect.top, rect.bottom);
                            if(buttonDistance<distance){
                                keep=b;
                                distance=buttonDistance;
                            }
                        }

                    }
                }
            }
        }
        //if non are selected let button be selected
        if(count==buttonMax){
            keep.setPressed(true);
        }
        //on release
        if(ev.getAction()==MotionEvent.ACTION_UP){
            keep.callOnClick();
            return false;
        }

        return super.onInterceptTouchEvent(ev);
    }

    static boolean isPointWithin(int x, int y, int x1, int x2, int y1, int y2) {
        return (x <= x2 && x >= x1 && y <= y2 && y >= y1);
    }

    static int distance(int x, int y,int x1, int x2, int y1, int y2){
        x1 = Math.abs(x1-x);
        x2 = Math.abs(x2-x);
        y1 = Math.abs(y1-y);
        y2 = Math.abs(y2-y);
        x = (x1>x2?x2:x1);
        y = (y1>y2?y2:y1);
        return x+y;
    }

}