Android Notes (System ADB UI)

Android系统架构

Android系统分四层：Linux内核层，库和运行时，Framework层和应用层。
- Linux包括硬件驱动，进程管理，安全系统
- Dalvik虚拟机，运行时编译；ART虚拟机安装时编译
- Framework
  - ActivityManager
  - BackupManager
  - Bluetooth
  - ContentProviders
  - LocationManger
  - Map libraries
  - MediaPlayer
  - NotificationManager
  - PackageManager
  - ResourceManager
  - SearchManager
  - SharedPreference
  - TelephoneManager
  - WidgetProvider
  - WindowManager
  - ViewSystem
  - XMPPService
- 标准库
  - Apache HTTP
  - OpenGL ES
  - Open SSL
  - SQLite
  - Webkit
  - ICU
- Android NDK/SDK APP(解压后包含内容中有)
  - AndroidManifeset
  - Dalvik Classes
  - Resource bundle
  - NDK APP中包含JNI lib
App组件
- Activity
- BroardCastReceiver
- ContentProvider
- Service
Context
- Application Context(应用启动时创建，整个生命周期)
- Activity Context
- Service Context
Android 源代码目录与系统目录
- Android源代码目录
- Makefile (自动化编译，定制规则)
- bionic (bionic C库)
- bootable (启动引导相关代码)
- build (系统编译规则等基础开发包配置)
- cts (Google兼容性测试标准)
- dalvik (dalvik虚拟机)
- development (应用程序开发)
- external (开源模块)
- frameworks (框架)
- hardware (硬件适配层HAL代码)
- out (编译完成后代码输出目录)
- packages (应用程序包)
- prebuilt (x86 arm 架构下预编译资源)
- sdk
- system (底层文件系统库，应用及组件)
- vendor (厂商定制代码)
Android 系统目录 (ADB ls命令查看系统目录)
- /system/app/ 系统app
- /system/bin/ Linux自带组件
- /system/build.prop/ 系统属性信息
- /system/fonts/ 字体
- /system/framework/ 核心文件，框架层
- /system/lib/ .so文件
- /system/media/ 音频，闹钟，短信，来电等铃声
- /system/usr/ 用户配置文件，键盘布局，共享，时区文件
- /data/app/ 安装或升级的app
- /data/data/ App数据文件，数据库等信息
- /data/system/ 系统信息
- /data/misc/ WIFI，蓝牙，签名，VPN等信息

Android 开发工具

SDK镜像地址 android-studio
Genymotion 安装arm架构Genymotion-ARM-Translation
Android Debug
ADB Command (SDK platform-tools)
- adb shell
- ls|grep “data” / cd data
- android list target 显示系统Android平台 id:1 or android-19
- adb install -r a.apk 重新安装保留数据，安装位置/data/local/tmp/a.apk
- adb push a.apk /system/app 文件写入存储系统，有权限时可以安装系统应用
- adb push /system/temp/ c:\Desktop 从手机获取文件
- adb shell -> logcat|grep “abc” 查看log
- adb remount(重新挂载系统分区，使系统分区重新可写) -> adb shell -> cd system/app -> rm a.apk
- adb shell df 查看系统盘符
- adb shell pm list packages -f 输出所有安装应用
- adb shell input keyevent 3 模拟按键输入 keycode
- adb shell input touchscreen swipe 18 655 18 500 模拟滑动输入
- adb shell dumpsys activity activities|grep “tencent” 列出activity 运行状态，过滤”tencent”
- pm list packages -f 列出所有package
- adb shell am start -n com.qiyi.video/org.qiyi.android.video.MainActivity 启动一个Activity
- adb shell screenrecord /sdcard/a.mp4 录制屏幕
- adb reboot 重启
- adb 命令来源
  - /frameworks/base/cmds/
  - /system/core/toolbox/

Android 自定义控件

控件架构 ContentView id为content的FrameLayout, onCreate()方法中调用setContentView()后ActivityManagerService会回调onResume()，此时系统才会把DecorView添加到PhoneWindow中，显示并完成绘制
View的测量
- onMeasure() MeasureSpec 32位int值，高2位为测量的模式，低30位为测量的大小
  - EXACTLY 精确值模式，具体数值
  - AT_MOST 最大值模式，尺寸不超过父控件允许的最大尺寸
  - UNSPECIFIED 不指定，自定义view时使用,如果View要支持wrap_content,重写onMeasure()指定wrap_content时的大小

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec),
                getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec));
    }

/**
 * 宽高值自定义，在wrap_content时如果没有指定大小就会默认填充整个父布局
 */
private int measureWidth(int measureSpec){
  int result=0;
  int specMode=MeasureSpec.getMoode(measureSpec);
  int specSize=MeasureSpec.getSize(measureSpec);
  
  if(specMode=MeasureSpec.EXACTLY){
    result=specSize;
  }else{
    result=200;
    if(specMode=MeasureSpec.AT_MOST){
    result=Math.min(result,specSize)
    }
  }
  return result;
}

View的绘制

重写onDraw(Canvas canvas)

Canvas 画板

canvas.drawBitmap(bitmap1,0,0,null);
canvas.drawBitmap(bitmap2,0,0,null);
装载画布
Canvas mCanvas=new Canvas(bitmap2);
mCanvas.drawXXX
刷新view的时候，bitmap2发生改变，没有把图形直接绘制在canvas,而是通过改变bitmap2
绘制复杂图形，绘制多个拆分的小图形单元

ViewGroup的测量
在wrap_content时遍历子View的大小，决定自己的大小，其他模式下通过具体的指定值设置大小。遍历子View，调用子View的Measure方法获得每一个子View 的测量结果，然后遍历子View进行布局Layout,重写onLayout()控制子View显示位置的逻辑，如果支持wrap_content需要重写onMeasure()
ViewGroup的绘制绘制背景颜色以及遍历子View的绘制
自定义View比较重要的回调方法
- onFinishInflate()
- onSizeChanged()
- onMeasure()
- onLayout()
- onDraw()
- onTouchEvent()
对原生控件扩展
- 改变绘制顺序，需要改变画布位置状态时，先保存状态，等改变后，再恢复
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  canvas.save();
  canvas.translate(10,0);
  super.onDraw(canvas);
  canvas.restore();
- LinearGradient,Matrix实项文字闪动效果，onSizeChanged()中初始化，根据宽度设置LinearGradient渐变渲染器

protected void onSizeChanged(int w,int h,int oldw,int oldh){
  super.onSizeChanged(w,h,oldw,oldh);
  if(mViewWidth==0){
      mViewWidth=getMeasureWidth();
  if(mViewWidth>0){
     //获取Paint,设置LinearGradient
     mPaint=getPaint();
     mLinearGradient=new LinearGradient(0,0,mViewWidth,0,new int[]   {Color.BLUE,Color.RED},null,Shader.TitleMode.CLAMP);
     //设置着色器 mPaint.setShader(mLinearGradient)
     //平移变换矩阵
     mGradientMatrix=new Matrix();
   }
  } 
}

public void onDraw(Canvas canvas){
  if(mGradientMatrix!=null){
    mTranslate+=mViewWidth/5;
    if(mTranslate>2*mViewWidth){
      mTranslate=-mViewWidth;
    }
    mGradientMatrix.setTranslate(mTranslate,0);
    mLinearGradient.setLocalMatrix(mGradientMatrix);
    postInvalidateDelayed(100);
  }
}

复合控件继承ViewGroup

定义属性 res/value/attrs.xml

<declare-styleable name="V">
  <attr name="title|size|background" format="string|dimension| reference|color"/>
</declare-styleable>

//获取TypedArray,存储了属性值
TypedArray ta=context.obtainStyledAttributes(attrs,R.styleable.V);
ta.getColor();
ta.getString();
ta.getDrawable();
ta.getDimension();
//资源回收
ta.recycle();

组合控件

mBtn1=new Button();
mBtn2=new Button();
mTextView=new TextView();
mParams=new LayoutParams();
mParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT,true);
addView(mBtn1,mParams);
addView(mBtn2,mParams);
addView(mTextView,mParams);

定义接口,添加事件
public method
include layout

重写View

比例图中间圆形加中心文字，外圈一定比例的圆弧 length 正方形边长

- 圆 
mCircle=length/2；mRadius=length/4; drawCirle()

- 圆弧
//所处的矩形框
mRect=new Rect(0.1*length,0.1*length,0.9*length,0.9*length);
drawArc(mRect,270,mSweepAngle,false,mArcPaint);
- 文字
drawText();

setSweepValue(100);

音频条形图

onSizeChanged()设置渐变色
onDraw() 绘制多个小矩形
postInvalidateDelayed(300)

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    mWidth = getWidth();
    Log.e("Audio", "mWidth=" + mWidth + "  w=" + w + "  h=" + h
            + "  oldw=" + oldw + "  oldh=" + oldh);
    mRectHeight = getHeight();
    mRectWidth = (int) (mWidth * 0.6 / mCount);
    mLinearGradient = new LinearGradient(0, 0, mRectWidth, mRectHeight, Color.YELLOW, Color.RED, Shader.TileMode.CLAMP);

    mMatrix = new Matrix();
    mPaint.setShader(mLinearGradient);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    mTranslate += mRectWidth / 5;
    if (mTranslate > 2 * mRectWidth) {
        mTranslate = -mRectWidth;
    }
    mMatrix.setTranslate(mTranslate, 0);
    mLinearGradient.setLocalMatrix(mMatrix);
    for (int i = 0; i < mCount; i++) {
        mCurrentHeight = (float) (mRectHeight * Math.random());
        canvas.drawRect((float) (mWidth * 0.2 + offset + mRectWidth * i), mCurrentHeight,
                (float) (mWidth * 0.2 + mRectWidth * (i + 1)), mRectHeight, mPaint);
    }
    postInvalidateDelayed(300);
}

自定义ViewGroup

重写onMeasure() onLayout() onTouchEvent()

自定义ScrollView，滑动后回位到item的起始位置

遍历的方式通知子View对自身测量

private void init() {
     mScroller = new OverScroller(getContext());
     mScreenHeight = getResources().getDisplayMetrics().heightPixels;
 }
 
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     int count=getChildCount();
     for (int i = 0; i < count; i++) {
         View child=getChildAt(i);
         measureChild(child,widthMeasureSpec,heightMeasureSpec);
     }
 }

对子View进行位置放置

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int childCount = getChildCount();
    int screenHeight = getResources().getDisplayMetrics().heightPixels;
    //获取整个ViewGroup高度
    MarginLayoutParams layoutParams = (MarginLayoutParams) getLayoutParams();
    layoutParams.height = childCount * screenHeight;
    setLayoutParams(layoutParams);
    for (int i = 0; i < childCount; i++) {
        View child = getChildAt(i);
        if (child.getVisibility() != View.GONE) {
            child.layout(l, screenHeight * i, r, screenHeight * (i + 1));
        }
    }
}

在onTouchEvent()中添加滑动事件，使用scrollBy()

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            mLastY =   event.getY();
            //起点
            mStart = getScrollY();
            break;
        case MotionEvent.ACTION_MOVE:
            if (!mScroller.isFinished()) {
                mScroller.abortAnimation();
            }
            float dy = mLastY - event.getY();
            Log.d("Scroll", "======" );
            Log.d("Scroll", "dy = " + dy);
            Log.d("Scroll", "getScrollY() = " + getScrollY());
            Log.d("Scroll", "getHeight()  = " + getHeight());
            Log.d("Scroll", "mScreenHeight()  = " + mScreenHeight);
            Log.d("Scroll", "getHeight() - mScreenHeight = " + (getHeight() - mScreenHeight));
            Log.d("Scroll", "mLastY = " + mLastY);
            Log.d("Scroll", "mStart = " + mStart);

            if (getScrollY() < 0) {
                //最顶端，超过0时，不再下拉
                //不设置这个，getScrollY一直是负数
                dy = 0;
            }
            if (getScrollY() > getHeight() - mScreenHeight) {
                //滑到最底端时，不再滑动
                //不设置这个，getScrollY一直是大于getHeight() - mScreenHeight的数
                dy = 0;
            }
            scrollBy(0, (int) dy);
            //不断的设置Y，在滑动的时候子view就会比较顺畅
            mLastY =  event.getY();
            break;
        case MotionEvent.ACTION_UP:
            mEnd = getScrollY();
            int dScrollY = mEnd - mStart;
            //向上，向下滑动，超过1/3屏幕高度，
            //结束滑动时滚动到下个位置，没有超过时复位
            if (dScrollY > 0) {
                if (dScrollY < mScreenHeight / 3) {
                    mScroller.startScroll(0, mEnd,
                            0, -dScrollY, 200);
                } else {
                    mScroller.startScroll(0, mEnd, 0,
                            mScreenHeight - dScrollY, 200);
                }
            } else {
                if (-dScrollY < mScreenHeight / 3) {
                    mScroller.startScroll(0, mEnd,
                            0, -dScrollY, 200);
                } else {
                    mScroller.startScroll(0, mEnd,
                            0, -(mScreenHeight + dScrollY), 200);
                }
            }
            break;
    }
    // 重绘执行computeScroll()
    postInvalidate();
    //需要返回true否则down后无法执行move和up操作
    return true;
}

/**
 * Scroller只是个计算器，提供插值计算，让滚动过程具有动画属性，
 * 但它并不是UI，也不是滑动辅助UI运动，反而是单纯地为滑动提供计算
 * 需要invalidate()之后才会调用,这个方法在onDraw()中调用
 */
@Override
public void computeScroll() {
    super.computeScroll();
    if (mScroller.computeScrollOffset()) {
        scrollTo(0, mScroller.getCurrY());
        postInvalidate();
    }
}

事件拦截机制，涉及触摸事件MotionEvent(),onTouchEvent()，dispatchTouchEvent(),onInterceptTouchEvent(),多个View,ViewGroup之间对事件的处理

ViewGroup A,B

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    Log.e("A","dispatchTouchEvent "+ev.getAction());
    return super.dispatchTouchEvent(ev);
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    Log.e("A","onInterceptTouchEvent "+ev.getAction());
    return super.onInterceptTouchEvent(ev);
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    Log.e("A","onTouchEvent "+ev.getAction());
    return super.onTouchEvent(ev);
}

View

@Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
      Log.e("MyView","dispatchTouchEvent "+ev.getAction());
      return super.dispatchTouchEvent(ev);
  }

  @Override
  public boolean onTouchEvent(MotionEvent ev) {
      Log.e("MyView","onTouchEvent "+ev.getAction());
      return super.onTouchEvent(ev);
  }

View位置顺序是A最外层，B中间，MyView最底层。传递分发机制是A->B->MyView,处理机制时MyView->B->A

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事件传递返回值：True 拦截，不继续传递；False,不拦截，继续传递
事件处理返回值：True 处理了不用传递回上级，False 给上级处理
初始情况都是False