Question

我正在尝试创建一个可以在您的设备上移动ImageView的应用，例如拖动，当我将75％的ImageView放出屏幕时显示{{1} }} 例如。我一直在阅读有关Toast和MotionEvent的信息，并且我已经关注question，但它并没有让我信服。

修改

我目前的代码是：

onTouchListener

我做了那些public class MainActivity extends AppCompatActivity implements View.OnTouchListener { int windowwidth; int windowheight; private ImageView mImageView; private ViewGroup mRrootLayout; private int _xDelta; private int _yDelta; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DisplayMetrics displaymetrics = new DisplayMetrics(); this.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics); windowwidth = displaymetrics.widthPixels; windowheight = displaymetrics.heightPixels; mRrootLayout = (ViewGroup) findViewById(R.id.root); mImageView = (ImageView) mRrootLayout.findViewById(R.id.im_move_zoom_rotate); RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(150, 150); mImageView.setLayoutParams(layoutParams); mImageView.setOnTouchListener(this); } public boolean onTouch(View view, MotionEvent event) { final int X = (int) event.getRawX(); final int Y = (int) event.getRawY(); if(X == 0){ Toast.makeText(this, "OUT", Toast.LENGTH_SHORT).show(); } else if (Y == 0){ Toast.makeText(this, "OUT", Toast.LENGTH_SHORT).show(); } switch (event.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) view.getLayoutParams(); _xDelta = X - lParams.leftMargin; _yDelta = Y - lParams.topMargin; break; case MotionEvent.ACTION_UP: break; case MotionEvent.ACTION_POINTER_DOWN: break; case MotionEvent.ACTION_POINTER_UP: break; case MotionEvent.ACTION_MOVE: RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view .getLayoutParams(); layoutParams.leftMargin = X - _xDelta; layoutParams.topMargin = Y - _yDelta; layoutParams.rightMargin = -250; layoutParams.bottomMargin = -250; view.setLayoutParams(layoutParams); break; } mRrootLayout.invalidate(); return true; } }和if只是为了知道else if是否已经离开设备，在设备的左侧和右侧看起来就像它一样好吧，但是我想让它更干净而不是硬写，我也不能得到ImageView 150为什么？另外，我不知道为什么我必须创建一个LayoutParams(150,150)以及为什么我必须放

RelativeLayout.LayoutParams

我做了layoutParams.rightMargin = -250; layoutParams.bottomMargin = -250;，因为当用户想要将if/else if放出设备时我想要删除，因此我需要控制他何时尝试，此时我才得到它TOP / LEFT / RIGHT不下来，我也得到我的设备的尺寸，只是为了尝试X或Y与高度相同或只是显示ImageView，但它没有正确执行。< / p>

现在我的Toast是ImageView，但它会更大（几乎是中间屏幕）。

注

如果您知道其他任何方式更容易或更干净，请随意将其放在这里，我不关心我的代码，我可以适应它，我只是希望它清晰而不是硬编码。

Answer 1

你的日常工作大部分都有效。在下面的代码中，我已经注释掉了不需要的部分，并为那些需要解释的部分制作了符号。以下是成品的样子：

此图解说明如何计算左边距。相同类型的计算适用于上边距。

<强> MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {

    int windowwidth; // Actually the width of the RelativeLayout.
    int windowheight; // Actually the height of the RelativeLayout.
    private ImageView mImageView;
    private ViewGroup mRrootLayout;
    private int _xDelta;
    private int _yDelta;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // We are interested when the image view leaves its parent RelativeLayout
        // container and not the screen, so the following code is not needed.
//        DisplayMetrics displaymetrics = new DisplayMetrics();
//        this.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
//        windowwidth = displaymetrics.widthPixels;
//        windowheight = displaymetrics.heightPixels;
        mRrootLayout = (ViewGroup) findViewById(R.id.root);
        mImageView = (ImageView) mRrootLayout.findViewById(R.id.im_move_zoom_rotate);

        // These these following 2 lines that address layoutparams set the width
        // and height of the ImageView to 150 pixels and, as a side effect, clear any
        // params that will interfere with movement of the ImageView.
        // We will rely on the XML to define the size and avoid anything that will
        // interfere, so we will comment these lines out. (You can test out how a layout parameter
        // can interfere by setting android:layout_centerInParent="true" in the ImageView.
//        RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(150, 150);
//        RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(150, 150);
//        mImageView.setLayoutParams(layoutParams);
        mImageView.setOnTouchListener(this);

        // Capture the width of the RelativeLayout once it is laid out.
        mRrootLayout.post(new Runnable() {
            @Override
            public void run() {
                windowwidth = mRrootLayout.getWidth();
                windowheight = mRrootLayout.getHeight();
            }
        });
    }

    // Tracks when we have reported that the image view is out of bounds so we
    // don't over report.
    private boolean isOutReported = false;

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

        // Check if the image view is out of the parent view and report it if it is.
        // Only report once the image goes out and don't stack toasts.
        if (isOut(view)) {
            if (!isOutReported) {
                isOutReported = true;
                Toast.makeText(this, "OUT", Toast.LENGTH_SHORT).show();
            }
        } else {
            isOutReported = false;
        }
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                // _xDelta and _yDelta record how far inside the view we have touched. These
                // values are used to compute new margins when the view is moved.
                _xDelta = X - view.getLeft();
                _yDelta = Y - view.getTop();
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_POINTER_DOWN:
            case MotionEvent.ACTION_POINTER_UP:
                // Do nothing
                break;
            case MotionEvent.ACTION_MOVE:
                RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams) view
                    .getLayoutParams();
                // Image is centered to start, but we need to unhitch it to move it around.
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                    lp.removeRule(RelativeLayout.CENTER_HORIZONTAL);
                    lp.removeRule(RelativeLayout.CENTER_VERTICAL);
                } else {
                    lp.addRule(RelativeLayout.CENTER_HORIZONTAL, 0);
                    lp.addRule(RelativeLayout.CENTER_VERTICAL, 0);
                }
                lp.leftMargin = X - _xDelta;
                lp.topMargin = Y - _yDelta;
                // Negative margins here ensure that we can move off the screen to the right
                // and on the bottom. Comment these lines out and you will see that
                // the image will be hemmed in on the right and bottom and will actually shrink.
                lp.rightMargin = view.getWidth() - lp.leftMargin - windowwidth;
                lp.bottomMargin = view.getHeight() - lp.topMargin - windowheight;
                view.setLayoutParams(lp);
                break;
        }
        // invalidate is redundant if layout params are set or not needed if they are not set.
//        mRrootLayout.invalidate();
        return true;
    }

    private boolean isOut(View view) {
        // Check to see if the view is out of bounds by calculating how many pixels
        // of the view must be out of bounds to and checking that at least that many
        // pixels are out.
        float percentageOut = 0.50f;
        int viewPctWidth = (int) (view.getWidth() * percentageOut);
        int viewPctHeight = (int) (view.getHeight() * percentageOut);

        return ((-view.getLeft() >= viewPctWidth) ||
            (view.getRight() - windowwidth) > viewPctWidth ||
            (-view.getTop() >= viewPctHeight) ||
            (view.getBottom() - windowheight) > viewPctHeight);
    }
}

<强> activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/im_move_zoom_rotate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:src="@drawable/circle" />

</RelativeLayout>

Answer 2

该框架有一个名为View.OnDragListener的类。请参阅Drag & Drop教程。

如果您想研究如何做到这一点，另请参阅DraggablePanel项目。

Answer 3

我正在使用此方法拖动ImageView，我希望这可以帮助您：所以我定义了这个类的属性：

convert[Data, Option](DataO(None)).

然后我在活动的OnCreate（）方法下实现此代码：

import scalaz.std.option.optionInstance
import shapeless.contrib.scalaz.functions._

case class DataO(i: Option[Int])    
case class Data(i: Int)

case class Converter[I, O]() {
  def convert[Ri <: HList, Ro, F[_]: Functor](d: I)(implicit GI: Generic.Aux[I, Ri], Se: Sequencer.Aux[Ri, F[Ro]], G: Generic.Aux[O, Ro]): F[O] = {
    val x = GI.to(d)
    val b = sequence(x)
    val y = Functor[F].map(b)(G.from)
    y
  }
}

//usage
Converter[DataO, Data].convert(DataO(Option(1)) // Some(Data(1))

Answer 4

如何使用onTouch移动RelativeLayout中包含的所有视图的工作示例。希望它会有所帮助：

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {
    private RelativeLayout mRelLay;
    private float mInitialX, mInitialY;
    private int mInitialLeft, mInitialTop;
    private View mMovingView = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRelLay = (RelativeLayout) findViewById(R.id.relativeLayout);

        for (int i = 0; i < mRelLay.getChildCount(); i++)
            mRelLay.getChildAt(i).setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        RelativeLayout.LayoutParams mLayoutParams;

        switch (motionEvent.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mMovingView = view;
                mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
                mInitialX = motionEvent.getRawX();
                mInitialY = motionEvent.getRawY();
                mInitialLeft = mLayoutParams.leftMargin;
                mInitialTop = mLayoutParams.topMargin;
                break;

            case MotionEvent.ACTION_MOVE:
                if (mMovingView != null) {
                    mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
                    mLayoutParams.leftMargin = (int) (mInitialLeft + motionEvent.getRawX() - mInitialX);
                    mLayoutParams.topMargin = (int) (mInitialTop + motionEvent.getRawY() - mInitialY);
                    mMovingView.setLayoutParams(mLayoutParams);
                }
                break;

            case MotionEvent.ACTION_UP:
                mMovingView = null;
                break;
        }

        return true;
    }
}

Answer 5

<强>更新

在步骤3中添加右/下边距以防止图像变焦。您可以看到如果不更改右/下边距，图像将按相对布局进行缩放。

getMeasuredHeight / Width避免MATCH_PARENT和WRAP_CONTENT。
如果有工具栏/操作栏，则topMargin + height > relativeLayout's height也适用于最终确定。

记录out of bound状态，避免连续出现toast。

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {

    Point lastPoint = new Point();
    RelativeLayout relativeLayout;

    boolean lastOutOfTop = false;
    boolean lastOutOfLeft = false;
    boolean lastOutOfRight = false;
    boolean lastOutOfBottom = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        (findViewById(R.id.imageView)).setOnTouchListener(this);
        relativeLayout = (RelativeLayout)findViewById(R.id.relativeLayout);
    }

    @Override
    public boolean onTouch(View view, MotionEvent event) {
        //1. user's finger
        final Point point = new Point((int) event.getRawX(), (int) event.getRawY());

        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                // 2. record the last touch point
                lastPoint = point;
                break;
            case MotionEvent.ACTION_UP:
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                break;
            case MotionEvent.ACTION_POINTER_UP:
                break;
            case MotionEvent.ACTION_MOVE:
                // 3. get the move offset
                final Point offset = new Point(point.x-lastPoint.x, point.y-lastPoint.y);
                RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view
                        .getLayoutParams();
                layoutParams.leftMargin += offset.x;
                layoutParams.topMargin += offset.y;
                // * also check right/bottom Margin
                layoutParams.rightMargin = relativeLayout.getMeasuredWidth() - layoutParams.leftMargin+view.getMeasuredWidth();
                layoutParams.bottomMargin = relativeLayout.getMeasuredHeight() - layoutParams.topMargin+view.getMeasuredHeight();
                view.setLayoutParams(layoutParams);
                // 4. record the last touch point
                lastPoint = point;
                break;
        }

        // 5. check bounds
        RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
        boolean outOfTop = layoutParams.topMargin < 0;
        boolean outOfLeft = layoutParams.leftMargin < 0;
        boolean outOfBottom = layoutParams.topMargin+view.getMeasuredHeight() > relativeLayout.getMeasuredHeight();
        boolean outOfRight = layoutParams.leftMargin+view.getMeasuredWidth() > relativeLayout.getMeasuredWidth();

        // 6. if out of bound
        if (outOfLeft&&!lastOutOfLeft) Toast.makeText(this, "OUT Left", Toast.LENGTH_SHORT).show();
        if (outOfTop&&!lastOutOfTop) Toast.makeText(this, "OUT Top", Toast.LENGTH_SHORT).show();
        if (outOfBottom&&lastOutOfBottom) Toast.makeText(this, "OUT Bottom", Toast.LENGTH_SHORT).show();
        if (outOfRight&&lastOutOfRight)  Toast.makeText(this, "OUT Right", Toast.LENGTH_SHORT).show();

        // 7. record
        lastOutOfTop = outOfTop;
        lastOutOfLeft = outOfLeft;
        lastOutOfBottom = outOfBottom;
        lastOutOfRight = outOfRight;
        return true;
    }
}

Answer 6

您可以通过此代码实现此目的。

DisplayMetrics metrics = getResources().getDisplayMetrics();
int windowWidth = metrics.widthPixels;
int windowHeight = metrics.heightPixels;

现在在onTouch方法中，计算目标位置是否超过上述尺寸。

if（currentXLocation + deltaX＆gt; windowWidth）{

// this will ensure that target location 
// is always <= windowHeight
deltaX = windowWidth - currentXLocation; 

} else if( currentXLocation + deltaX < 0){

deltaX = -(currentXLocation);

} else if (...){

// perform similar calculations for the rest 

}

Android - 在屏幕上移动ImageView（像拖动一样）

修改

注

6 个答案: