主程序中有俩个.java文件，分别如下。在layout中设置了android:background="@drawable/cc",然而被没有出现背景图片，还是黑兮兮的一片。求大牛帮助，不甚感激。
代码如下：
MainActivity.java
package com.example.homework;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
public class MainActivity extends Activity {
public static MainActivity instance;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
instance = this;
//设置全屏
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
requestWindowFeature(Window.FEATURE_NO_TITLE);
//显示自定义的SurfaceView视图
setContentView(new MySurfaceView(this));
}
}
MySurfaceView.java文件
package com.example.homework;
import android.app.Service;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.SurfaceHolder.Callback;
public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;
private int screenW, screenH;
//声明一个传感器管理器
private SensorManager sm;
//声明一个传感器
private Sensor sensor;
//声明一个传感器监听器
private SensorEventListener mySensorListener;
//圆形的X,Y坐标
private int arc_x, arc_y;
//传感器的xyz值
private float x = 0, y = 0, z = 0;
/**
* SurfaceView初始化函数
*/
public MySurfaceView(Context context) {
super(context);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
//获取传感器管理类实例
sm = (SensorManager) MainActivity.instance.getSystemService(Service.SENSOR_SERVICE);
//实例一个重力传感器实例
sensor = sm.getDefaultSensor(Sensor.TYPE_GRAVITY);
//实例传感器监听器
mySensorListener = new SensorEventListener() {
@Override
//传感器获取值发生改变时在响应此函数
public void onSensorChanged(SensorEvent event) {
x = event.values[0];
//x>0 说明当前手机左翻 x<0右翻
y = event.values[1];
//y>0 说明当前手机下翻 y<0上翻
z = event.values[2];
//z>0 手机屏幕朝上 z<0 手机屏幕朝下
arc_x -= x;
arc_y += y;
}
@Override
//传感器的精度发生改变时响应此函数
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
//为传感器注册监听器
sm.registerListener(mySensorListener, sensor, SensorManager.SENSOR_DELAY_NORMAL);
}
/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
screenW = this.getWidth();
screenH = this.getHeight();
flag = true;
//实例线程
th = new Thread(this);
//启动线程
th.start();
}
/**
* 游戏绘图
*/
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.BLACK);
paint.setColor(Color.RED);
canvas.drawArc(new RectF(arc_x, arc_y, arc_x + 50, arc_y + 50), 0, 360, true, paint);
paint.setColor(Color.YELLOW);
canvas.drawText("当前重力传感器的值:", arc_x - 50, arc_y - 30, paint);
canvas.drawText("x=" + x+" "+ "y=" + y +" "+ "z=" + z, arc_x - 50, arc_y, paint);
String temp_str = "温馨提示： ";
String temp_str2 = "";
String temp_str3 = "";
if (x < 1 && x > -1 && y < 1 && y > -1) {
temp_str2 += "当前手机处于水平放置的状态";
if (z > 0) {
temp_str3 += "并且屏幕朝上"+" "+"X轴的测试值:" + x + " " + "Y轴的测试值:" + y + " "
+ "Z轴的测试值:" + z;
} else {
temp_str3 += "并且屏幕朝下,提示别躺着玩手机，对眼睛不好哟~"+" "+"X轴的测试值:" + x + " " + "Y轴的测试值:" + y + " "
+ "Z轴的测试值:" + z;
}
} else {
if (x > 1) {
temp_str2 += "当前手机处于向左翻的状态"+" ";
} else if (x < -1) {
temp_str2 += "当前手机处于向右翻的状态"+" ";
}
if (y > 1) {
temp_str2 += "当前手机处于向下翻的状态"+" ";
} else if (y < -1) {
temp_str2 += "当前手机处于向上翻的状态"+" ";
}
if (z > 0) {
temp_str3 += "并且屏幕朝上"+" "+"X轴的测试值:" + x + " " + "Y轴的测试值:" + y + " "
+ "Z轴的测试值:" + z;
} else {
temp_str3 += "并且屏幕朝下,提示别躺着玩手机，对眼睛不好哟~"+" "+"X轴的测试值:" + x + " " + "Y轴的测试值:" + y + " "
+ "Z轴的测试值:" + z;
}
}
paint.setTextSize(10);
canvas.drawText(temp_str, 0, 50, paint);
canvas.drawText(temp_str2, 0, 80, paint);
canvas.drawText(temp_str3, 0, 110, paint);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}
/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
return true;
}
/**
* 按键事件监听
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return super.onKeyDown(keyCode, event);
}
/**
* 游戏逻辑
*/
private void logic() {
}
@Override
public void run() {
while (flag) {
long start = System.currentTimeMillis();
myDraw();
logic();
long end = System.currentTimeMillis();
try {
if (end - start < 50) {
Thread.sleep(50 - (end - start));
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag = false;
}
}
以下是布局文件代码
<?xml version="1.0" encoding="utf-8"?>
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/cc"
>
