Android0916（自定義的View，Converse的簡單繪圖）

自定義的View

自定義的控件有的是View和ViewGroup。這裏先練一下自定義的View，說到自定義的View，即利用主線程對UI界面進行繪製，自定義的View自然要繼承與View，其中要重寫OnMeasure()（測量畫布的寬和高的方法）和OnDraw()（繪製的方法Canvas畫布），還有要實現兩個構造器分別是
View（Content content），View（Content content，AttributeSet attra）

繪製簡單的一個表

在activity_main.xml中引用自定義的View時要將自定義的View的所在位置全稱寫出來，activity_main.xml如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

   <com.example.administrator.canvas.widget.MyView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content" />

</LinearLayout>

MyView.java自定義的View寫在另一個繼承於View的類裏，

public class MyView extends View {
    private int width;
    private int height;
    private Paint mPaintLine;
    private Paint mPaintCircle;
    private Paint mPaintText;
    private Calendar mCalendar;
    private Paint mPaintMinute;
    private Paint mPaintHour;
    private Paint mPaintSecond;
    private static final int HANDLE_SECOND=0;
    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch(msg.what){
                case HANDLE_SECOND:
                    mCalendar=Calendar.getInstance();
                    invalidate();//告訴UI主線程重新繪製
                    handler.sendEmptyMessageDelayed(HANDLE_SECOND, 1000);
                    break;
            }
        }
    };
    public MyView(Context context) {
        //創建視圖時使用的簡單構造函數。
        super(context);
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mCalendar=Calendar.getInstance();
        //畫線的畫筆
        mPaintLine =new Paint();
        mPaintLine.setColor(Color.RED);//設置顯得顏色
        mPaintLine.setStrokeWidth(10);//設置線的寬度
        //畫圓的畫筆
        mPaintCircle=new Paint();
        mPaintCircle.setStrokeWidth(10);//設置線的寬度
        mPaintCircle.setColor(Color.GREEN);//設置線的顏色
        mPaintCircle.setStyle(Paint.Style.STROKE);//設置圓的空心
        //寫字的畫筆
        mPaintText=new Paint();
        mPaintText.setTextSize(30);
        mPaintText.setColor(Color.BLACK);
        mPaintText.setTextAlign(Paint.Align.CENTER);
        //畫分針的畫筆
        mPaintMinute=new Paint();
        mPaintMinute.setStrokeWidth(10);
        mPaintMinute.setColor(Color.YELLOW);
        //畫時針的畫筆
        mPaintHour=new Paint();
        mPaintHour.setStrokeWidth(15);
        mPaintHour.setColor(Color.GREEN);
        //畫秒針的畫筆
        mPaintSecond=new Paint();
        mPaintSecond.setColor(Color.RED);
        mPaintSecond.setStrokeWidth(5);
        //設置秒針走動
        handler.sendEmptyMessageDelayed(HANDLE_SECOND, 2000);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);
        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);
        setMeasuredDimension(width,height);//設置畫布的大小，長和寬
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //是由UI主線程自動調用，只需要在此繪製即可
//        canvas.drawLine(0,0,300,300,mPaintLine);
//        canvas.drawCircle(300,300,100,mPaintCircle);
        canvas.drawCircle(width/2,height/2,300,mPaintCircle);
        canvas.drawCircle(width/2,height/2,10,mPaintCircle);
        //繪製錶盤的刻度
        for (int i=1;i<=12;i++){
//            canvas.save();
            canvas.rotate(360/12,width/2,height/2);
            canvas.drawLine(width/2,height/2-300,width/2,height/2-270,mPaintLine);
            canvas.drawText(""+i,width/2,height/2-240,mPaintText);
//            canvas.restore();
        }
        int minute=mCalendar.get(Calendar.MINUTE);
        int hour=mCalendar.get(Calendar.HOUR);
        int second=mCalendar.get(Calendar.SECOND);
        //繪製分針；
        float degree=minute/60f*360;
        canvas.save();
        canvas.rotate(degree,width/2,height/2);
        canvas.drawLine(width/2,height/2-200,width/2,height/2+20,mPaintMinute);
        canvas.restore();
        //繪製時針
        float hourDegree=(hour*60+minute)/12f/60*360;
        canvas.save();
        canvas.rotate(hourDegree,width/2,height/2);
        canvas.drawLine(width/2,height/2-150,width/2,height/2+20,mPaintHour);
        canvas.restore();
        //繪製秒針
        canvas.save();//將當前矩陣和剪輯保存到私有堆棧上。
        canvas.rotate(second*6,width/2,height/2);
        canvas.drawLine(width/2,height/2-230,width/2,height/2+20,mPaintSecond);
        canvas.restore();//用來去除所有修改最後一次調用保存的的矩陣/剪輯
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

繪製下載進度

圓形進度圖
AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.administrator.canvas" >

    <application
        android:allowBackup="true"
        android:icon="@mipmap/openofficeorg_draw"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical">
<Button
    android:id="@+id/btn_download"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="開始下載"/>
    <com.example.administrator.canvas.widget.MyProgress
        android:id="@+id/myprogress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    </LinearLayout>
</LinearLayout>

MyProgress.java

public class MyProgress extends View{
    private int width;
    private int height;
    private int currentProgress;
    private Paint mPaintBackGround;
    private Paint mPaintCurrent;
    private Paint mPaintText;
    private int maxProgress=100;
    //得到進度的最大值
    public int getMaxProgress() {
        return maxProgress;
    }
    //設置進度的最大值
    public void setMaxProgress(int maxProgress) {
        this.maxProgress = maxProgress;
    }
    //得到當前的進度值
    public int getCurrentProgress(){
        return currentProgress;
    }
    //設置當前的進度值
    public void setCurrentProgress(int currentProgress){
        this.currentProgress=currentProgress;
        invalidate();//刷新
    }

    public MyProgress(Context context) {
        super(context);
    }

    public MyProgress(Context context, AttributeSet attrs) {
        super(context, attrs);

        mPaintBackGround=new Paint();
        mPaintBackGround.setColor(Color.CYAN);
        mPaintBackGround.setAntiAlias(true);//消除鋸齒

        mPaintCurrent=new Paint();
        mPaintCurrent.setColor(Color.GREEN);
        mPaintCurrent.setAntiAlias(true);

        mPaintText=new Paint();
        mPaintText.setColor(Color.BLACK);
        mPaintText.setTextSize(80);
        mPaintText.setTextAlign(Paint.Align.CENTER);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);
        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);
        setMeasuredDimension(width,height);//設置畫布的大小，長和寬
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(width/2,height/8,100,mPaintBackGround);//設置背景的圖形
        //設置當前下載進度的圖形
        canvas.drawCircle(width/2,height/8,100f*currentProgress/maxProgress,mPaintCurrent);
        //設置當前下載進度的文字顯示
        canvas.drawText(currentProgress+"%",width/2,height/4,mPaintText);
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private MyProgress myProgress;
    private static final int PORGRESS=0x23;
    private Button btn_download;
    private int progrress;
    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch(msg.what){
                case PORGRESS:
                    progrress++;
                    if (progrress<=100){
                        myProgress.setCurrentProgress(progrress);
                        handler.sendEmptyMessageDelayed(PORGRESS,20);
                    }
                    break;
            }
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myProgress= (MyProgress) findViewById(R.id.myprogress);
        btn_download= (Button) findViewById(R.id.btn_download);
        btn_download.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.sendEmptyMessageDelayed(PORGRESS,10);

            }
        });
    }
}