在我的应用程序中,我使用MainActivity类中的Canvas对象绘制某些图形。之后,当用户在屏幕上滑动时,我使用自定义视图在先前创建的图形上绘制水平和垂直线。
问题是MainActivity和CustomView之间存在轻微的坐标偏移。由于这个原因,我的线条与游戏中的其他图形对象不一致。为了确认这一点,我从MainActivity和我的CustomView类进行了以下调用:
canvas.drawLine(0,0,50,50,paint);
结果是两条平行线。 CustomView的原点位于手机的右上角,MainActivity类的原点有一定的偏移量。
(截图:http://i.stack.imgur.com/x3BDK.png)
如果有人能指出这里可能存在的问题,我将不胜感激。
以下是相关文件:
activity_main.xml中
<com.example.offsettest.CustomLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/customLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
android:paddingLeft="0dp"
android:paddingRight="0dp"
android:paddingBottom="0dp"
android:paddingTop="0dp"
android:layout_marginLeft="0dp"
android:layout_marginRight="0dp"
android:layout_marginTop="0dp"
android:layout_marginBottom="0dp">
</com.example.offsettest.CustomLayout>
MainActivity.java
package com.example.offsettest;
import com.rgtech.offsettest.R;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.Menu;
import android.widget.ImageView;
public class MainActivity extends Activity {
private Bitmap bitmap;
private Canvas mCanvas;
private Paint paint;
private CustomLayout customLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
draw();
}
public void draw(){
DisplayMetrics metrics = this.getResources().getDisplayMetrics();
float width = metrics.widthPixels;
float height = metrics.heightPixels;
bitmap = Bitmap.createBitmap((int) width, (int) height, Config.RGB_565);
mCanvas = new Canvas(bitmap);
mCanvas.drawColor(Color.GREEN);
paint = new Paint();
paint.setAntiAlias(true);
customLayout = (CustomLayout) findViewById(R.id.customLayout);
ImageView imageView = new ImageView(this);
imageView.setImageBitmap(bitmap);
imageView.setPadding(0, 0, 0, 0);
customLayout.addView(imageView);
paint.setColor(Color.BLACK);
mCanvas.drawLine(0, 0, 50, 50, paint);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
CustomLayout.java
package com.example.offsettest;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.LinearLayout;
@SuppressLint("NewApi")
public class CustomLayout extends LinearLayout{
private Paint paint = new Paint();
public CustomLayout(Context context) {
super(context);
}
public CustomLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomLayout(Context context, AttributeSet attrs,int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
paint.setDither(true);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
canvas.drawLine(0, 0, 50, 50, paint);
}
}
除了这些文件外,我只在清单文件中设置了android:theme =“@ android:style / Theme.NoTitleBar”。
答案 0 :(得分:0)
解决此问题的最简单方法是删除图像视图的填充或边距或布局的根视图。 (如果有的话)
另一种可能性是分别使用view.getX()
view.getRawX()
计算左上角位置之间的偏移/距离(对于Y也是如此),然后在(0, 0, 50, 50)
但不是{ (offsetX, offsetY, 50 + offsetX, 50 + offsetY)
。
imageView.setAdjustViewBounds(true);
解决了这个问题。
MainActivity.java中的draw方法现在应如下所示:
public void draw() {
DisplayMetrics metrics = this.getResources().getDisplayMetrics();
float width = metrics.widthPixels;
float height = metrics.heightPixels;
bitmap = Bitmap.createBitmap((int) width, (int) height, Config.RGB_565);
mCanvas = new Canvas(bitmap);
mCanvas.drawColor(Color.GREEN);
paint = new Paint();
paint.setAntiAlias(true);
customLayout = (CustomLayout) findViewById(R.id.customLayout);
ImageView imageView = new ImageView(this);
imageView.setImageBitmap(bitmap);
imageView.setPadding(0, 0, 0, 0);
imageView.setAdjustViewBounds(true); // call this method
customLayout.addView(imageView);
paint.setColor(Color.BLACK);
mCanvas.drawLine(0, 0, 50, 50, paint);
}