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我想在asynctask内的SurfaceView上绘制分形,但我不知道如何正确执行它。我的想法是创建包含进度条的surfaceview(在主要活动中),而单独的线程将计算将绘制哪些像素并将其存储在某种“缓冲区”(我使用canvas)。之后,应绘制表面视图结果(这会破坏进度条的旋转轮)。Android:与asynctask螺纹绘图
我写这段代码:
MainActivity.java
public class MainActivity extends Activity {
private Complex constant;
private int bg_color, fg_color;
private static final int nMax = 30, rMax = 2;
private class JuliaThread extends AsyncTask<Complex, Void, Canvas> {
private double re, im, w, h;
private Complex sequence;
private int i;
private Canvas canv;
private Paint p;
private View m;
@Override
protected void onPreExecute() {
super.onPreExecute();
m = (View) findViewById(R.id.sv);
w = m.getWidth();
h = m.getHeight();
canv = new Canvas();
p = new Paint();
}
@Override
protected Canvas doInBackground(Complex... c) {
for (double y=0; y<h; y++) {
for (double x=0; x<w; x++) {
re = (x/w)*3.0-1.5;
im = -(y/h)*3.0-1.5;
sequence = new Complex(re, im);
for (i=1; i<=nMax; i++) {
sequence = sequence.square();
sequence.add(c[0]);
if (sequence.abs() > rMax) break;
}
if (i == nMax) p.setColor(fg_color);
else p.setColor(bg_color);
canv.drawLine((float)x, (float)y, (float)x, (float)y, p);
}
}
return canv;
}
@Override
protected void onPostExecute(Canvas result) {
super.onPostExecute(result);
m.draw(result);
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
constant = new Complex(-0.391, -0.587);
bg_color = Color.rgb(0, 0, 0);
fg_color = Color.rgb(255, 255, 255);
new JuliaThread().execute(constant);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
activity_main.xml中
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:id="@+id/mainview" >
<SurfaceView
android:id="@+id/sv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true" >
</SurfaceView>
<ProgressBar
android:id="@+id/progressBar1"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/sv"
android:layout_centerHorizontal="true"
android:layout_marginTop="138dp" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/progressBar1"
android:layout_centerHorizontal="true"
android:layout_marginTop="15dp"
android:text="@string/loading"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
不幸的是,这种方法是行不通的。你能解释我吗,我做错了什么,以及如何正确地做到这一点?
我不知道如何做到这一点与asynctask ...?我创建了扩展SurfaceView的类,实现了SurfaceHolder.Callback,但我不知道如何获得这个“mSurfaceHolder” – TeoTN