Question

我正在创建一个需要自定义布局的应用程序。但是在运行我的应用程序之后，简单的强制关闭。如果可能的话，任何人都可以建议原因和解决方案

提前完成

这是我的主要活动

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }  
}

这是我的自定义布局类

public class Odo extends View {
    private Paint p;
    private RectF rect;
    public Odo(Context context) {
        super(context);
        Log.e("odo", "constructor");
        init();
        // TODO Auto-generated constructor stub
    }
    public void init() {
        Log.e("odo", "inside init()");
        rect = new RectF();
        p = new Paint(Paint.ANTI_ALIAS_FLAG);
        p.setColor(Color.GREEN);

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        // TODO Auto-generated method stub
        super.onSizeChanged(w, h, oldw, oldh);
        Log.e("odo", "inside onSizeChange");
        rect.set(0, 0, w, h);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        Log.e("odo", "inside onDraw");
        super.onDraw(canvas);

        canvas.drawRect(rect, p);

    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // TODO Auto-generated method stub
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        Log.e("odo", "inside onMeasure");
    }
}

这是我的XML文件

<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" >
    <com.example.odo.Odo
        android:id="@+id/odom"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
         />
</LinearLayout>

Answer 1

在自定义视图中，您需要覆盖带有AttributeSet参数的构造函数，以便在XML布局中使用它：

只需替换

public Odo(Context context) {
    super(context);
    Log.e("odo", "constructor");
    init();
    // TODO Auto-generated constructor stub
}

通过

public Odo(Context context, AttributeSet attrs) {
    super(context, attrs);
    Log.e("odo", "constructor");
    init();
    // TODO Auto-generated constructor stub
}

Answer 2

我认为你需要提供默认的构造函数，它将AttributeSet和/或int用于样式引用。例如：

public class Odo extends View {
    private Paint p;
    private RectF rect;

    public Odo(Context context) {
        super(context);
        Log.e("odo", "constructor");
        init();
        // TODO Auto-generated constructor stub
    }

    public Odo (Context context, AttributeSet attrs) {
        super(context, attrs);
        Log.e("odo", "constructor");
        init();
    }

    public Odo (Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        Log.e("odo", "constructor");
        init();
    }

    public void init() {
        Log.e("odo", "inside init()");
        rect = new RectF();
        p = new Paint(Paint.ANTI_ALIAS_FLAG);
        p.setColor(Color.GREEN);

    }

//.....  and so on

}

应用程序已强制关闭

2 个答案: