Question

我有问题。我用按钮等创建了一个类DrawingView，并在我称之为

的活动上

public class PaintActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        DrawingView view=new DrawingView(this);
        setContentView(view);
        addContentView(view.btnEraseAll, view.params);
    }

这是我的配置

class DrawingView extends View  {

private Paint brush = new Paint();
private Path path = new Path();
public Button btnEraseAll, btnAccept, btnBack;
public ViewGroup.LayoutParams params;

public DrawingView(Context context) {

    super(context);
    brush.setAntiAlias(true);
    brush.setColor(Color.BLACK);
    brush.setStyle(Paint.Style.STROKE);
    brush.setStrokeJoin(Paint.Join.ROUND);
    brush.setStrokeWidth(22f);
    btnEraseAll = new Button(context);
    btnEraseAll.setText("Clear");
    btnAccept = new Button(context);
    btnAccept.setText("Accept");
    btnBack = new Button(context);
    btnBack.setText("Back");
    params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT);
    btnEraseAll.setLayoutParams(params);
    btnAccept.setLayoutParams(params);
    btnBack.setLayoutParams(params);
    btnEraseAll.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {
            path.reset();
            postInvalidate();
        }

    });

}

@Override

protected void onDraw(Canvas canvas) {

    canvas.drawPath(path, brush);
}

public boolean onTouchEvent(MotionEvent event) {
    float pointX = event.getX();
    float pointY = event.getY();
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(pointX, pointY);
            return true;
        case MotionEvent.ACTION_MOVE:
            path.lineTo(pointX, pointY);
            break;
        default:
            return false;
    }
    postInvalidate();

    return false;

}

}

但是如何在活动主页上添加更多按钮（我有3个）？在这里我添加按钮

 addContentView(view.btnEraseAll, view.params);

但我想添加这个按钮

btnAccept, btnBack;

谁能帮助我吗？我想在视图中添加3个按钮。

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/monitor"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/MyCustomActionBar">
        <activity
            android:name=".MainActivity"
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

Answer 1

我重构了一些代码，以便更轻松地进行操作。我还提取了.xml中的按钮，而不是以编程方式创建它们，因为它更容易。我还将DrawingView提取到一个单独的类中。我也对它进行了测试，以确保它有效。

(wts,)

<强> activity_paint.xml

public class PaintActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_paint);
        final DrawingView drawingView = (DrawingView) findViewById(R.id.drawing_canvas);
        View clearBtn = findViewById(R.id.btn_clear);
        clearBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                drawingView.reset();
            }
        });
    }
}

class DrawingView extends View {

    private Paint brush = new Paint();
    private Path path = new Path();

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

    private void init() {
        brush.setAntiAlias(true);
        brush.setColor(Color.BLACK);
        brush.setStyle(Paint.Style.STROKE);
        brush.setStrokeJoin(Paint.Join.ROUND);
        brush.setStrokeWidth(22f);
    }

    public void reset() {
        path.reset();
        postInvalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawPath(path, brush);
    }

    public boolean onTouchEvent(MotionEvent event) {
        float pointX = event.getX();
        float pointY = event.getY();
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                path.moveTo(pointX, pointY);
                return true;
            case MotionEvent.ACTION_MOVE:
                path.lineTo(pointX, pointY);
                break;
            default:
                return false;
        }
        postInvalidate();
        return false;
    }
}

<强> ids.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.example.myapplication.DrawingView
        android:id="@+id/drawing_canvas"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <Button
        android:id="@+id/btn_clear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:text="Clear"/>

    <Button
        android:id="@+id/btn_accept"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Accept"/>

    <Button
        android:id="@+id/btn_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:text="Back"/>

</RelativeLayout>

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如何向活动添加更多视图，按钮

1 个答案: