安卓基础：自定义View

其他 2018-09-15 06:26:32 阅读次数: 0

一.自定义View分类

View下面有

  • ImageView
    ImageButton
    QuickContactBadge
    AppCompatImageView

  • TextView
    EditText
    Button
    RadioButton
    ToggleButton
    CheckBox
    Switch
    TextClock
    Chronometer
    RowHeaderView

  • ViewGruop
    LinearLayout
    ReativeLayout
    ViewPager
    AbsoiuteLayout
    FrameLayout
    GridLayout
    TextureView
    ViewStub
    TabLtem
    Spce

二.时钟案例

一.新建一个类,继承View

package com.example.myapplication.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Build;
import android.support.annotation.Nullable;
import android.support.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.View;

import com.example.myapplication.R;

/**
 * Created by lyj on 2018/6/15.
 */

public class MyView extends View {

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

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
}

二.重写onDraw方法里面定义画笔，画东西

Paint paint = new Paint();

设置颜色

paint.setColor(Color.RED);

设置抗锯齿

paint.setAntiAlias(true);

画一个圆，把表盘背景图设置进去

Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.watch);
        RectF rectF = new RectF(getWidth() / 4+25, getHeight() / 2 - getWidth() / 4+25, getWidth() / 4 * 3-25, getHeight() / 2 + getHeight() / 8);
        canvas.drawBitmap(bitmap, null, rectF, paint);

画时针

canvas.save();
 canvas.rotate(hours * 30 + minute * 30 / 60, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(5);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 55, paint);
        canvas.restore();

画分针

canvas.save();
        canvas.rotate(minute * 6, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(3);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2 + 12, getHeight() / 2 - getHeight() / 8 + 40, paint);
        canvas.restore();

画秒针

canvas.save();
        canvas.rotate(second * 6, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(1);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2 + 15, getHeight() / 2 - getHeight() / 8 + 20, paint);
        canvas.restore();

画刻度

 for (int i = 0; i <= 60; i++) {
            canvas.save();
            canvas.rotate(6 * i, getWidth() / 2, getHeight() / 2);
            paint.setStrokeWidth(2);
            if (i % 5 == 0) {
                paint.setStrokeWidth(8);
                canvas.drawLine(getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 20, getWidth() / 2, getHeight() / 2 - getWidth() / 4 + 35, paint);
            } else {
                paint.setStrokeWidth(4);
                canvas.drawLine(getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 20, getWidth() / 2, getHeight() / 2 - getWidth() / 4+40, paint);

            }
            canvas.restore();
        }

注意：每画完一个图形都需要canvas.save();保存一下

三.实现指针动起来 (重点)

重新写一个 refresh方法

public void refresh(int h, int m, int s) {
        this.hours = h;
        this.minute = m;
        this.second = s;
        invalidate();//再次触发onDraw方法
    }

新建类完整的代码

package com.example.myapplication.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Build;
import android.support.annotation.Nullable;
import android.support.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.View;

import com.example.myapplication.R;

/**
 * Created by lyj on 2018/6/15.
 */

public class MyView extends View {
    private int hours = 20;
    private int minute = 20;
    private int second = 0;

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

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        //设置颜色
        paint.setColor(Color.RED);
        //抗锯齿
        paint.setAntiAlias(true);
        /*
        前两个参数：圆心的位置
        第三参数：半径
         */
        //canvas.drawCircle(getWidth()/2,getHeight()/2,getWidth()/4,paint);

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.watch);
        RectF rectF = new RectF(getWidth() / 4+25, getHeight() / 2 - getWidth() / 4+25, getWidth() / 4 * 3-25, getHeight() / 2 + getHeight() / 8);
        canvas.drawBitmap(bitmap, null, rectF, paint);

        //画直线(时针)
        canvas.save();
        canvas.rotate(hours * 30 + minute * 30 / 60, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(5);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 55, paint);
        canvas.restore();
        //画直线(分针)
        canvas.save();
        canvas.rotate(minute * 6, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(3);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2 + 12, getHeight() / 2 - getHeight() / 8 + 40, paint);
        canvas.restore();

        //画直线(秒针)
        canvas.save();
        canvas.rotate(second * 6, getWidth() / 2, getHeight() / 2);
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(1);
        canvas.drawLine(getWidth() / 2, getHeight() / 2, getWidth() / 2 + 15, getHeight() / 2 - getHeight() / 8 + 20, paint);
        canvas.restore();

        for (int i = 0; i <= 60; i++) {
            canvas.save();
            canvas.rotate(6 * i, getWidth() / 2, getHeight() / 2);
            paint.setStrokeWidth(2);
            if (i % 5 == 0) {
                paint.setStrokeWidth(8);
                canvas.drawLine(getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 20, getWidth() / 2, getHeight() / 2 - getWidth() / 4 + 35, paint);
            } else {
                paint.setStrokeWidth(4);
                canvas.drawLine(getWidth() / 2, getHeight() / 2 - getHeight() / 8 + 20, getWidth() / 2, getHeight() / 2 - getWidth() / 4+40, paint);

            }
            canvas.restore();
        }

    }

    public void refresh(int h, int m, int s) {
        this.hours = h;
        this.minute = m;
        this.second = s;
        invalidate();//再次触发onDraw方法
    }
}

activity类中获取当前时间

 Calendar calendar = Calendar.getInstance();
        hours = calendar.get(Calendar.HOUR_OF_DAY);
        minute = calendar.get(Calendar.MINUTE);
        second = calendar.get(Calendar.SECOND);

主线程不能做耗时操作，所以开启一个线程让指针动起来

new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    second++;
                    if (second == 60) {
                        second = 0;
                        minute++;
                    }
                    try {
                        Message message = handler.obtainMessage();
                        message.what = hours;
                        message.arg1 = minute;
                        message.arg2 = second;
                        handler.sendMessage(message);
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();

activity类的完整代码

package com.example.myapplication.view;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.example.myapplication.R;

import java.util.Calendar;

public class MyViewActivity extends AppCompatActivity {
    private MyView myView;
    private int hours;
    private int minute;
    private int second;
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            myView.refresh(msg.what, msg.arg1, msg.arg2);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my_view);

        myView = findViewById(R.id.my_view);

        Calendar calendar = Calendar.getInstance();
        hours = calendar.get(Calendar.HOUR_OF_DAY);
        minute = calendar.get(Calendar.MINUTE);
        second = calendar.get(Calendar.SECOND);

        myView.refresh(hours, minute, second);

        new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    second++;
                    if (second == 60) {
                        second = 0;
                        minute++;
                    }
                    try {
                        Message message = handler.obtainMessage();
                        message.what = hours;
                        message.arg1 = minute;
                        message.arg2 = second;
                        handler.sendMessage(message);
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }
}

布局文件需要引入自己的控件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.myapplication.view.MyViewActivity">
    <com.example.myapplication.view.MyView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/my_view"/>
</LinearLayout>

这里写图片描述

三.圆形imgView

新建一个类继承ImageView

package com.example.myapplication.view;

        import android.annotation.SuppressLint;
        import android.content.Context;
        import android.graphics.Bitmap;
        import android.graphics.BitmapShader;
        import android.graphics.Canvas;
        import android.graphics.Matrix;
        import android.graphics.Paint;
        import android.graphics.Shader;
        import android.graphics.drawable.BitmapDrawable;
        import android.graphics.drawable.Drawable;
        import android.util.AttributeSet;
        import android.widget.ImageView;

/**
 * Created by lyj on 2018/6/15.
 */

@SuppressLint("AppCompatCustomView")
public class MyImageView extends ImageView{
    private Paint mPaint; //画笔

    private int mRadius; //圆形图片的半径

    private float mScale; //图片的缩放比例
    public MyImageView(Context context) {
        super(context);
    }

    public MyImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int size = Math.min(getMeasuredWidth(), getMeasuredHeight());
        mRadius = size / 2;

        setMeasuredDimension(size, size);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        mPaint = new Paint();
        Bitmap bitmap = drawableToBitmap(getDrawable());

        //初始化BitmapShader，传入bitmap对象
        BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

        //计算缩放比例
        mScale = (mRadius * 2.0f) / Math.min(bitmap.getHeight(), bitmap.getWidth());

        Matrix matrix = new Matrix();
        matrix.setScale(mScale, mScale);
        bitmapShader.setLocalMatrix(matrix);


        mPaint.setShader(bitmapShader);

        //画圆形，指定好中心点坐标、半径、画笔
        canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
    }

    //写一个drawble转BitMap的方法
    private Bitmap drawableToBitmap(Drawable drawable) {
        if (drawable instanceof BitmapDrawable) {
            BitmapDrawable bd = (BitmapDrawable) drawable;
            return bd.getBitmap();
        }
        int w = drawable.getIntrinsicWidth();
        int h = drawable.getIntrinsicHeight();
        Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, w, h);
        drawable.draw(canvas);
        return bitmap;

    }
}

布局文件引入自定义图片控件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.myapplication.view.MyImageActivity">
    <com.example.myapplication.view.MyImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@mipmap/a"
        android:id="@+id/img_myView"/>

</LinearLayout>

这里写图片描述

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