我是一名业余程序员,一直在玩android开发。我目前正在尝试生成分形高度图。为了测试地图是否正确生成,我需要能够将地图绘制到屏幕上。这就是我遇到麻烦的地方。
这是我的 MainActivity、DrawMap 类(我的 onDraw() 所在的位置)和 CanvasThread() 类的代码。
主要活动:
package com.psstudios.HMG;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.view.View.OnClickListener;
import android.util.Log;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
Button Startgen = null;
Boolean run=true;
private void log(String text) {
Log.d("heightmap",text);
AppendLog app = new AppendLog(text);
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Startgen = (Button) findViewById(R.id.startgen);
log("loop");
Startgen.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
log("Starting world generation");
WorldGen world=new WorldGen(200,200);
log("World generation complete, drawing heightmap");
setContentView(new DrawMap(MainActivity.this, world));
log("Went too far");
}
});
run=false;
}
}
绘制地图:
package com.psstudios.HMG;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Bitmap;
import android.graphics.Bitmap.*;
import android.graphics.Paint;
import android.graphics.Color;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.util.Log;
import android.util.*;
public class DrawMap extends SurfaceView implements SurfaceHolder.Callback
{
int drawtype=1; //variable for which type of map to draw
Bitmap drawbitmap=null;
CanvasThread canvasThread=null;
Boolean run= true;
int Worldx=200;
int Worldy=200;
WorldGen _world=null;
public void log(String text){
Log.d("Heightmap", text);
AppendLog app = new AppendLog(text);
}
public void init(){
log("init();");
canvasThread=new CanvasThread(getHolder(), this);
setFocusable(true);
log("Post-CanvasThread");
}
public DrawMap(Context context){
super(context);
log("DrawMap(Context context)");
getHolder().addCallback(this);
init();
}
public DrawMap(Context context, AttributeSet attrs) {
super(context, attrs);
log("DrawMap(Context context, AttributeSet attrs)");
getHolder().addCallback(this);
init();
}
public DrawMap(Context context,WorldGen world){
super(context);
log("DrawMap(Context context, WorldGen world)");
getHolder().addCallback(this);
_world=world;
init();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format,int width, int height){
log("surfaceChanged()");
}
@Override
public void surfaceCreated(SurfaceHolder holder){
log("Surface Created");
canvasThread.setRunning(true);
canvasThread.run();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder){
log("Surface Destroyed");
Boolean retry = true;
canvasThread.setRunning(false);
while(retry){
try {
canvasThread.join();
retry=false;
} catch (InterruptedException e) {
//we will try again and again
}
}
}
@Override
public void onDraw(Canvas canvas){
log("onDraw()");
Paint paint = new Paint();
Paint paint2 = new Paint();
//canvas.drawColor(Color.BLACK);
paint.setColor(Color.WHITE);
paint.setStrokeWidth(10);
paint2.setColor(Color.BLUE);
for(int x=0; x<Worldx-1; x++){
for(int y=0; y<Worldy-1; y++){
//log(x + " : " + y);
canvas.drawPoint(x+20, y+20, paint);
canvas.drawPoint(x+220, y+220, paint2);
}
}
}
}
画布线程:
package com.psstudios.HMG;
import android.graphics.Canvas;
import android.view.*;
import android.util.Log;
public class CanvasThread extends Thread
{
private SurfaceHolder _surfaceHolder;
private DrawMap _drawMap;
private Boolean _run = false;
private void log(String text){
Log.d("HeightmapGen",text);
AppendLog app = new AppendLog(text);
}
public CanvasThread(SurfaceHolder surfaceHolder, DrawMap drawMap){
_surfaceHolder=surfaceHolder;
_drawMap=drawMap;
log("CanvasThread()");
}
public void setRunning(Boolean run){
log("setRunning()");
_run=run;
}
@Override
public void run() {
log("run()");
Canvas c;
while(_run){
c=null;
try{
c=_surfaceHolder.lockCanvas(null);
synchronized (_surfaceHolder) {
_drawMap.onDraw(c);
}
} finally {
if(c != null){
_surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
该程序使其进入 onDraw(); 函数,并通过 for 循环运行,但屏幕上没有显示任何内容。我想我错过了一些非常愚蠢的东西,但我似乎无法弄清楚出了什么问题。
提前感谢你们可以给我的任何帮助。