android之cpu使用率曲线效果的实现！

最近做一个效果：在手机设置里面“关于手机”里面添加一项来显示当前手机cpu使用率的曲线！其实现效果如下图所示：

上图关于手机的第一项就是我要实现的效果！今天来讲讲这个曲线的view（cpu_speedcurve_view）是如何实现的！

首先要注意以下几点：

（1）由于我设计的cpu_speedcurve_view不仅仅显示动态的曲线，还需要用textview显示一些cpu相关信息！所以，我选择cpu_speedcurve_view继承一个viewgroup，这里我选择的是FrameLayout

（3）曲线的怎么绘制？

           这里我是在cpu_speedcurve_view的public void draw(Canvas canvas)里面用Canvas的drawPath来绘制的。具体代码如下：

	public void draw(Canvas canvas) {
		super.draw(canvas);

		//mPaint.setColor(coordinateColor);
		//mPaint.setStrokeWidth(mStrokeSize*2);	
		//canvas.drawPath(m_path_coordinate, mPaint);
		//canvas.clipRect(10, 10, 5, 5);
		if(flag_start){
			if(m_path_0 == null && m_path_1 == null){
				//Start_run_CpuTracker_to_show_curve();
			}else{
				mPaint.setColor(curveColor);
				mPaint.setStrokeWidth(mStrokeSize);

				if(m_path_0 != null){
					// Log.d("speedcurve", "cpu_speedcurve_view  draw  (m_path != null) ");
					if(!m_path_0.isEmpty()){
						canvas.drawPath(m_path_0, mPaint);
					}
				}
				if(m_path_1 != null){
					// Log.d("speedcurve", "cpu_speedcurve_view  draw  (m_path != null) ");
					if(!m_path_1.isEmpty()){
						canvas.drawPath(m_path_1, mPaint);
					}
				}

			}
		}

	}

	private Path m_path_0;
	private Path m_path_1;

（2）对于曲线的动态显示，我的办法是定义一个Handler定时的自动发送信息来更新cpu运行的数据，最后用invalidate();来刷新曲线：

	private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case 000: 
					m_CpuTracker.update();
					TotalCpuPercent = m_CpuTracker.getTotalCpuPercent();
					int h = view_h - 2;

					//int CpuPercent_po = (int) (h * TotalCpuPercent);
					if(flag_num < 400){
						if(m_path_0 == null){
							m_path_0 = new Path();
							m_path_0.moveTo(view_w+4, h - TotalCpuPercent);
						}

						if(flag_num > 200){
							if(m_path_1 == null){
								m_path_1 = new Path();
								m_path_1.moveTo(view_w+4, h - TotalCpuPercent);
							}

						}else{
							m_path_1 = null;
						}
					}else if(flag_num < 600){
						m_path_0 = null;
						if(m_path_1 == null){
							m_path_1 = new Path();
							m_path_1.moveTo(view_w+4, h - TotalCpuPercent);
						}

					}else if(flag_num < 800){
						if(m_path_0 == null){
							m_path_0 = new Path();
							m_path_0.moveTo(view_w+4, h - TotalCpuPercent);
						}

					}else{
						flag_num = 0;
					}
					
					if(m_path_0 != null){
						m_path_0.lineTo(view_w+4, h - TotalCpuPercent);
						matrix.setTranslate(-4,0);
						m_path_0.transform(matrix);
					}
					
					if(m_path_1 != null){
						m_path_1.lineTo(view_w+4, h - TotalCpuPercent);
						matrix.setTranslate(-4,0);
						m_path_1.transform(matrix);
					}

				//	Log.d("speedcurve", "cpu_speedcurve_view  handleMessage  msg.what=000 flag_num="+flag_num);
				//	Log.d("speedcurve", "cpu_speedcurve_view  handleMessage  TotalCpuPercent="+TotalCpuPercent+"view_h="+view_h+"getCurCpuFreq()="+Cpu_info_manager.getCurCpuFreq());
				    if(flag_start){
						mHandler.sendEmptyMessageDelayed(000,300);
						invalidate();
						flag_num++;
					}else{
						Stop_run_CpuTracker_to_show_curve();
					}
					break;
                case 111: 

                	break;
            }
        }
    };

（3）如何获取cpu的使用率呢？

      用android提供的ProcessCpuTracker就可以了。

m_CpuTracker = new ProcessCpuTracker(false);

（4）最后记得 在这个里面 protected void onDetachedFromWindow()停止运行就可以了！

就这样问题就基本解决了！如果要实现如上的效果图的则需要定义一个PreferenceGroup：

		PreferenceGroup mCPUStatusPref = (PreferenceGroup) findPreference("cpu_key");      
		mCPUStatusPref.setLayoutResource(R.layout.cpu_curve_preference); 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="85dip"
    android:gravity="center_vertical"
    android:paddingStart="@*android:dimen/preference_item_padding_side"
    android:paddingEnd="?android:attr/scrollbarSize"
    android:background="?android:attr/selectableItemBackground"
    android:paddingTop="6dip"
    android:paddingBottom="6dip">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:paddingTop="6dip"
        android:paddingBottom="6dip">

        <TextView
            android:id="@+android:id/title"
            android:text="@string/XunHu_Setting_Cpu_Info"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:singleLine="true"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:ellipsize="marquee"
            android:fadingEdge="horizontal" />

        <TextView
            android:id="@android:id/summary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/usage_type_cpu_foreground"
            android:layout_below="@android:id/title"
            android:layout_alignStart="@android:id/title"
            android:visibility="gone"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:textColor="?android:attr/textColorSecondary"
            android:maxLines="4" />

    </RelativeLayout>

    <com.android.settings.widget.cpu_speedcurve_view
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:minWidth="180dip"
        android:background="@drawable/cpu_curve_bg"
        android:layout_marginBottom="8dip"
        android:layout_marginTop="8dip"
        >

	 <TextView
		 android:id="@+android:id/cpu_speedcurve_view_title"
		 android:text="@string/XunHu_Setting_Cpu_Info_util"	
		 android:layout_width="wrap_content"
		 android:layout_height="wrap_content"
		 android:singleLine="true"
		 android:ellipsize="marquee"
		 android:fadingEdge="horizontal" />

	 </com.android.settings.widget.cpu_speedcurve_view>

</LinearLayout>