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最新推荐文章于 2024-07-10 03:14:41 发布

冯昕睿feng

最新推荐文章于 2024-07-10 03:14:41 发布

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分类专栏： android

本文链接：https://blog.youkuaiyun.com/qq_33413264/article/details/89893204

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博客介绍了绘制矩形的两种方法，一是在代码中进行add操作，二是在布局中进行add操作。

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绘制一个矩形

public class AView extends View {
    private static final String TAG = "FackMask";

    private Paint paint;
    private Rect rect;

    private int left;
    private int top;
    private int right;
    private int bottom;

    private Canvas canvas;


    public AView(Context context){
        super(context);
        initPaint();
    }

    public AView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
        initPaint();
    }

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


    /**
     * 外部调用的接口
     * */
    public void setRect(int left,int top,int right,int bottom){
        this.left=left;
        this.top=top;
        this.right=right;
        this.bottom=bottom;
        Log.d(TAG, "setRect: 控件");
        postInvalidate();
        invalidate();//更新调用onDraw重新绘制
    }



    private void initPaint(){
        paint=new Paint();
        left=100;
        top=100;
        right=300;
        bottom=300;
    }



    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);//设置空心
        rect=new Rect(left,top,right,bottom);
        canvas.drawRect(rect,paint);
    }
}

方法一，在代码中add

public class MainActivity extends AppCompatActivity {
    private Button bt1;
    private AView aView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt1=findViewById(R.id.bt1);
        LinearLayout linearLayout = findViewById(R.id.main);
        aView = new AView(MainActivity.this);
        linearLayout.addView(aView);
        bt1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                aView.setRect(200,200,800,800);
            }
        });


//        aView=findViewById(R.id.aa);
//        bt1.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                aView.setRect(200,200,800,800);
//            }
//        });
    }
}

2，在布局中add

public class MainActivity extends AppCompatActivity {
    private Button bt1;
    private AView aView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt1=findViewById(R.id.bt1);
        LinearLayout linearLayout = findViewById(R.id.main);
//        aView = new AView(MainActivity.this);
//        linearLayout.addView(aView);
//        bt1.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                aView.setRect(200,200,800,800);
//            }
//        });


        aView=findViewById(R.id.aa);
        bt1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                aView.setRect(200,200,800,800);
            }
        });
    }
}

<?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"
    android:id="@+id/main"
    tools:context=".MainActivity">
    <Button
        android:id="@+id/bt1"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        />

    <com.dtsz.dtsz.myapplication.AView
        android:id="@+id/aa"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        />

</LinearLayout>