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java - 在 Android 中更改自定义 View 的宽度和高度

转载 作者:塔克拉玛干 更新时间:2023-11-02 20:06:13 24 4
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在我的 android 应用程序中,我有一个裁剪图像。因此,我将自定义 View 编程为我的裁剪框。我可以移动裁剪框。但我的问题是如何拖动裁剪框的边框并更改它的宽度和高度。我该怎么做?

属性类:

public class Attr {

public static final float CROP_BOX_START_X = 5;
public static final float CROP_BOX_START_Y = 5;
public static final float CROP_BOX_END_X = 305;
public static final float CROP_BOX_END_Y = 105;

}

裁剪框类:

public class CropBox extends View {

private Paint paint = new Paint();


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

public CropBox(Context context, AttributeSet attributeSet) {
super(context, attributeSet);
}


@Override
public void onDraw(Canvas canvas) {
float[][] circleXY = {
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y},
{(Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y},
{(Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_START_X, (Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2},
{Attr.CROP_BOX_END_X, (Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2}
};
float[][] lineXY = {
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y}
};

paint.setColor(Color.CYAN);
paint.setStrokeWidth(1);

for(int i = 0 ; i < circleXY.length ; i++)
canvas.drawCircle(circleXY[i][0], circleXY[i][1], 5, paint);

paint.setStrokeWidth(2);

for(int i = 0 ; i < lineXY.length ; i++)
canvas.drawLine(lineXY[i][0], lineXY[i][2], lineXY[i][2], lineXY[i][3], paint);
}

}

CropTestActivity 类:

public class CropTestActivity extends Activity {

private ImageView imageView;
private CropBox cropBox;
private RelativeLayout relativeLayout;
private RelativeLayout.LayoutParams layoutParams;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.crop_test_layout);
imageView = (ImageView)findViewById(R.id.android_image);
cropBox = new CropBox(this);
relativeLayout = (RelativeLayout)findViewById(R.id.crop_test_layout);
layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, RelativeLayout.LayoutParams.FILL_PARENT);
imageView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
public void onGlobalLayout() {
imageView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
layoutParams.leftMargin = imageView.getWidth() / 2 - (int)((Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2) + imageView.getLeft();
layoutParams.topMargin = imageView.getHeight() / 2 - (int)((Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2) + imageView.getTop();
}
});
relativeLayout.addView(cropBox, layoutParams);
cropBox.setOnTouchListener(new Crop(imageView));
}

}

裁剪等级:

public class Crop implements OnTouchListener {

private static final int NONE = 0;
private static final int BOX_DRAG = 1;
private static final int BORDER_DRAG = 2;

private int mode = NONE;

private float cropBoxStartX = Attr.CROP_BOX_START_X;
private float cropBoxStartY = Attr.CROP_BOX_START_Y;
private float cropBoxEndX = Attr.CROP_BOX_END_X;
private float cropBoxEndY = Attr.CROP_BOX_END_Y;

private ImageView imageView;

private PointF start = new PointF();


public Crop(ImageView imageView) {
this.imageView = imageView;
}


public boolean onTouch(View view, MotionEvent event) {
RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams)view.getLayoutParams();

switch(event.getAction() & MotionEvent.ACTION_MASK) {

case MotionEvent.ACTION_DOWN:
start.set(event.getX(), event.getY());
if(event.getX() > cropBoxStartX && event.getX() < cropBoxEndX && event.getY() > cropBoxStartY && event.getY() < cropBoxEndY)
mode = BOX_DRAG;
else if(event.getX() == cropBoxStartX || event.getX() == cropBoxEndX || event.getY() == cropBoxStartY || event.getY() == cropBoxEndY)
mode = BORDER_DRAG;
else
mode = NONE;
break;

case MotionEvent.ACTION_UP:
mode = NONE;
break;

case MotionEvent.ACTION_MOVE:
if(mode == BOX_DRAG) {
layoutParams.leftMargin = (int)event.getX() - (int)start.x + view.getLeft();
layoutParams.topMargin = (int)event.getY() - (int)start.y + view.getTop();
while(layoutParams.topMargin + 5 < imageView.getTop())
layoutParams.topMargin++;
while(layoutParams.leftMargin + (cropBoxEndX - cropBoxStartX + 5) > imageView.getRight())
layoutParams.leftMargin--;
while(layoutParams.topMargin + (cropBoxEndY - cropBoxStartY + 5) > imageView.getBottom())
layoutParams.topMargin--;
while(layoutParams.leftMargin + 5 < imageView.getLeft())
layoutParams.leftMargin++;
}
else if(mode == BORDER_DRAG) {
}
break;
}
view.setLayoutParams(layoutParams);
return true;
}

}

布局 XML:

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/crop_test_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >

<ImageView
android:id="@+id/android_image"
android:src="@drawable/android"
android:layout_width="fill_parent"
android:layout_height="300dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:layout_marginBottom="10dp"
android:layout_marginLeft="10dp"
android:layout_gravity="center"
android:scaleType="fitXY"
android:contentDescription="@string/android_image_description" >
</ImageView>

</RelativeLayout>

调整大小之前:

enter image description here

调整大小后:

enter image description here

感谢您的帮助。

最佳答案

解决方案如下,

从 Activity 修改 onCreate

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.crop_test_layout);
imageView = (ImageView)findViewById(R.id.android_image);
cropBox = new CropBox(this, imageView);
relativeLayout = (RelativeLayout)findViewById(R.id.crop_test_layout);
relativeLayout.addView(cropBox);
}

修改后的 CropBox 类:

public class CropBox extends View {

private static final int CROP_BOX_START_X = 5;
private static final int CROP_BOX_START_Y = 5;
private static final int CROP_BOX_END_X = 305;
private static final int CROP_BOX_END_Y = 105;

private static final int DRAG_SQUARE = 75;

public ImageView mImageView;
boolean mIsFirstClick = false;

private Paint paint = new Paint();
private Rect mRect;

public CropBox(Context context, ImageView aBaseView) {
super(context);
mImageView = aBaseView;
mRect = new Rect(CROP_BOX_START_X, CROP_BOX_START_Y, CROP_BOX_END_X, CROP_BOX_END_Y);
setOnTouchListener(new Crop());
}

public CropBox(Context context, AttributeSet attributeSet) {
super(context, attributeSet);
}

@Override
public void onDraw(Canvas canvas) {

paint.setStrokeWidth(2);

paint.setColor(Color.CYAN);
paint.setStyle(Paint.Style.STROKE);

canvas.drawRect(mRect, paint);

canvas.drawLine(mRect.right-DRAG_SQUARE, mRect.bottom-DRAG_SQUARE,
mRect.right, mRect.bottom-DRAG_SQUARE, paint);

canvas.drawLine(mRect.right-DRAG_SQUARE, mRect.bottom-DRAG_SQUARE,
mRect.right-DRAG_SQUARE, mRect.bottom, paint);
}

class Crop implements OnTouchListener {

private static final int NONE = 0;
private static final int BOX_DRAG = 1;
private static final int BORDER_DRAG = 2;

private int mode = NONE;

private PointF start = new PointF();

public boolean onTouch(View view, MotionEvent event) {
RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams)view.getLayoutParams();

switch(event.getAction() & MotionEvent.ACTION_MASK) {

case MotionEvent.ACTION_DOWN:
start.set(event.getX(), event.getY());

if((event.getX() <= mRect.right && event.getX() >=(mRect.right - DRAG_SQUARE))
&& (event.getY() >= mRect.top && event.getY() >=(mRect.bottom - DRAG_SQUARE))){
mode = BORDER_DRAG;
mIsFirstClick = false;
}
else if(mRect.contains((int)event.getX(), (int)event.getY())) {
mode = BOX_DRAG;
if (mIsFirstClick){
mRect = new Rect(CROP_BOX_START_X, CROP_BOX_START_Y,
CROP_BOX_END_X, CROP_BOX_END_Y);
mIsFirstClick = false;
} else {
mIsFirstClick = true;
}
}
else{
mode = NONE;
mIsFirstClick = true;
}
break;

case MotionEvent.ACTION_UP:
mode = NONE;
break;

case MotionEvent.ACTION_MOVE:
mIsFirstClick = false;
if(mode == BOX_DRAG) {
layoutParams.leftMargin = (int)event.getX() - (int)start.x + view.getLeft();
layoutParams.topMargin = (int)event.getY() - (int)start.y + view.getTop();
}
else if(mode == BORDER_DRAG) {
if (event.getX() > view.getLeft() && event.getY() > view.getTop()){
mRect.right = (int) event.getX();
mRect.bottom = (int) event.getY();
}
}
while(layoutParams.topMargin + 5 < mImageView.getTop())
layoutParams.topMargin++;
while(layoutParams.leftMargin + mRect.right > mImageView.getRight())
layoutParams.leftMargin--;
while(layoutParams.topMargin + mRect.bottom > mImageView.getBottom())
layoutParams.topMargin--;
while(layoutParams.leftMargin + 5 < mImageView.getLeft())
layoutParams.leftMargin++;
break;
}
view.setLayoutParams(layoutParams);
invalidate();
return true;
}
}
}

我想提几点。

  • 在 CropBox 中合并 Attr 和 Crop
  • 无需从线条创建矩形。您可以使用 Rect
  • 切勿在 Draw 方法中初始化数组/对象
  • 添加了一个功能:如果在矩形上双击它会返回到原来的位置
  • 在 ImageView 中限制矩形可能会有一些问题。我相信您可以解决这些问题...:)

除此之外,还有另一种使用 Canvas 缩放的有趣方式 Image in Canvas with touch events使用该类而不是 Cropbox 并尝试一下。

希望对你有帮助..

关于java - 在 Android 中更改自定义 View 的宽度和高度,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12230371/

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