自定义View

程序员文章站 2022-05-30 20:19:11

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1.自定义View分类
2.时钟案例
3.圆形ImageView

View分类
ImageView

ImageButton
QuickContactBadge
AppCompatImageView
TextView
EditText
Button
RadioButton
ToggleButton
CheckBox
Switch
TextClock
Chronometer
RowHeaderView

ViewGroup

LinearLayout
RelativeLayout
ViewPager
ListView
AbsoulteLayout
FrameLayout
GridLayout

TextureView
ViewStub
Tabltem
Space

时钟案例
onDraw方法

 protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint=new Paint();
        paint.setColor(Color.RED);
        paint.setAntiAlias(true);
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.watch);
        RectF rectF = new RectF(getWidth() / 4+20, getHeight() / 2 - getWidth() / 4+25, getWidth() / 4 * 3-25, getHeight() /2 + getHeight() / 8);
        canvas.drawBitmap(bitmap, null, rectF, paint);

表盘背景

 Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.watch);
        RectF rectF = new RectF(getWidth() / 4+20, getHeight() / 2 - getWidth() / 4+25, getWidth() / 4 * 3-25, getHeight() /2 + getHeight() / 8);
        canvas.drawBitmap(bitmap, null, rectF, paint);

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();

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();

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();

完整代码

package com.example.a17708.pratice;

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;

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();
        paint.setColor(Color.RED);
        paint.setAntiAlias(true);
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.watch);
        RectF rectF = new RectF(getWidth() / 4+20, 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
    }
}

package com.example.a17708.pratice;

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

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();
    }
}

自定义View
圆形ImageView

package com.example.a17708.pratice;

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;


@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;

    }

}

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