Android自定义组件之自动换行View

浏览数：22 / 时间：2015年06月11日

　　做Android这么长时间，对自定义组件这块知识了解的很少。之前公司项目里有个模块需求是自动换行，今天重新写个组件实现这个效果。

效果图如下：

　　组件是继承的ViewGroup,在用的时候调用addView方法把TextView加进去，然后该组件会把textview放到合适的位置。

WordWrapView.java

public class WordWrapView extends ViewGroup {
    private static final int PADDING_HOR = 10;//水平方向padding
    private static final int PADDING_VERTICAL = 5;//垂直方向padding
    private static final int SIDE_MARGIN = 10;//左右间距
    private static final int TEXT_MARGIN = 10;
    /**
     * @param context
     */
    public WordWrapView(Context context) {
        super(context);
    }
    
    /**
     * @param context
     * @param attrs
     * @param defStyle
     */
    public WordWrapView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }



    /**
     * @param context
     * @param attrs
     */
    public WordWrapView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }



    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childCount = getChildCount();
        int autualWidth = r - l;
        int x = SIDE_MARGIN;// 横坐标开始
        int y = 0;//纵坐标开始
        int rows = 1;
        for(int i=0;i<childCount;i++){
            View view = getChildAt(i);
            view.setBackgroundColor(Color.GREEN);
            int width = view.getMeasuredWidth();
            int height = view.getMeasuredHeight();
            x += width+TEXT_MARGIN;
            if(x>autualWidth){
                x = width+SIDE_MARGIN;
                rows++;
            }
            y = rows*(height+TEXT_MARGIN);
            if(i==0){
                view.layout(x-width-TEXT_MARGIN, y-height, x-TEXT_MARGIN, y);
            }else{
                view.layout(x-width, y-height, x, y);
            }
        }
    };

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int x = 0;//横坐标
        int y = 0;//纵坐标
        int rows = 1;//总行数
        int specWidth = MeasureSpec.getSize(widthMeasureSpec);
        int actualWidth = specWidth - SIDE_MARGIN * 2;//实际宽度
        int childCount = getChildCount();
        for(int index = 0;index<childCount;index++){
            View child = getChildAt(index);
            child.setPadding(PADDING_HOR, PADDING_VERTICAL, PADDING_HOR, PADDING_VERTICAL);
            child.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
            int width = child.getMeasuredWidth();
            int height = child.getMeasuredHeight();
            x += width+TEXT_MARGIN;
            if(x>actualWidth){//换行
                x = width;
                rows++;
            }
            y = rows*(height+TEXT_MARGIN);
        }
        setMeasuredDimension(actualWidth, y);
    }

}

View Code

MainActivity.java

public class MainActivity extends Activity {

    private WordWrapView wordWrapView;
    private String[] strs = new String[] { "哲学系", "新疆维吾尔族自治区", "新闻学", "心理学",
            "犯罪心理学", "明明白白", "西方文学史", "计算机", "掌声", "心太软", "生命",
            "程序开发" };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        wordWrapView = (WordWrapView) this.findViewById(R.id.view_wordwrap);
        for (int i = 0; i < 12; i++) {
            TextView textview = new TextView(this);
            textview.setText(strs[i]);
            wordWrapView.addView(textview);
        }
    }

}

View Code

activity_main.xml

<RelativeLayout 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"
    tools:context=".MainActivity" >

    <com.winhoo.viewtest.widget.WordWrapView
        android:id="@+id/view_wordwrap"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        />

</RelativeLayout>