加速球（内存的变化）

clean.png

主界面

public class MainActivity extends AppCompatActivity implements  View.OnClickListener{
private ImageView imageView;
private SpeedView speedView;
private TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageView = (ImageView) findViewById(R.id.img_main);
    speedView = (SpeedView) findViewById(R.id.myview_main_speed);
    textView = (TextView) findViewById(R.id.tv_main);
    long available= Memory.availableMemory();//调取Memory的方法
    long total=Memory.totalMemory();
    double rote=(total-available)*0.8/total;
    int round= (int) (rote*360);
    int text= (int) (rote*100);
    speedView.setSweepAngle(round);
    textView.setText(text+" ");
    imageView.setOnClickListener(this);
}

@Override
public void onClick(View v) {
    if (v.getId()==R.id.img_main||v.getId()==R.id.tv_main){
       //仅仅是为了能模拟，这里应该为实际的值
        long available= Memory.availableMemory();
        long total=Memory.totalMemory();
        double rote=(total-available)*0.8/total*0.7;
        int round= (int) (rote*360);
        int text= (int) (rote*100);
        speedView.setSweepAngle(round);
        textView.setText(text+"");
    }
}
}

自己编译的布局View，即变化的扇形

public class SpeedView extends View {
private RectF rectF;
private Paint paint;
private int sweepAngle=90;
private int a,data=0;
private boolean isrun;
private Timer timer;
private int[] dotiem={5,8,9,12,8,5};


public SpeedView(Context context) {
    //调用下面的
    this(context,null);
}

public SpeedView(Context context, @Nullable AttributeSet attrs) {
    this(context, attrs,0);
}

public SpeedView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    //画笔
    paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setColor(Color.parseColor("#ff9736"));

}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);
    //rect矩形
    rectF = new RectF(0,0,width, height);
    //设置
    setMeasuredDimension(width,height);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawArc(rectF,-90,sweepAngle,true,paint);
}

public void setSweepAngle(final int toAngle){

    //防止有人一直点
    if (isrun)return;
    //计时器
    timer = new Timer(false);
    TimerTask  timerTask=new TimerTask() {
        int goStar=0;
        @Override
        public void run() {
            switch (goStar){
                //退回去
                case 0:
                    isrun=true;
                    sweepAngle-=dotiem[data++];
                    if (data>=dotiem.length){
                        data=0;
                    }
                    if (sweepAngle<=0){
                        sweepAngle=0;
                        goStar=1;
                    }
                    break;
                //前进
                case 1:
                    sweepAngle+=dotiem[data++];
                    if (data>=dotiem.length){
                        data=0;
                    }
                    if (sweepAngle>= toAngle) {
                        sweepAngle =  toAngle;
                        timer.cancel();
                        isrun=false;
                        data=0;
                        goStar = 0;

                    }
                    //刷新界面
                    postInvalidate();
                    break;

            }


        }
    };
    //代表每隔40毫秒停留50毫秒
    timer.schedule(timerTask,40,50);
}
}

加速球所在的布局。xml

 
//自己编辑的扇形


//自己定义的选择器

选择器（写在res的drawable）

读取内存的代码

public class Memory {
public static long availableMemory(){
    //想管理者请求
    ActivityManager  manager= (ActivityManager) App.appcontext.getSystemService(Context.ACTIVITY_SERVICE);
    //请求内存信息
    ActivityManager.MemoryInfo memoryInfo=new ActivityManager.MemoryInfo();
    manager.getMemoryInfo(memoryInfo);
    //返回一个可用的内存
    return memoryInfo.availMem;
}
public static long totalMemory(){
    //想管理者请求
    ActivityManager manager = (ActivityManager) App.appcontext.getSystemService(Context.ACTIVITY_SERVICE);
    //请求内存信息
    ActivityManager.MemoryInfo memoryInfo=new ActivityManager.MemoryInfo();
    manager.getMemoryInfo(memoryInfo);
    //返回一个总的内存
    return memoryInfo.totalMem;
}
}

APP承接上下文的，新建java

public class App extends Application{
public static App appcontext;
@Override
public void onCreate() {
    super.onCreate();
    appcontext=this;
}
 }