Android自定义控件----继承ViewGroup自定义实现流式布局

1效果图：

2项目结构

3思路：

• 1自定义ViewGrounp,写一个类继承ViewGrounp
• 2重写onMeasure();测量子View的宽高，设置自己的宽高；
• onMeasure()根据子View的布局文件，为子View设置测量模式和测量值
• 测量=测量模式+测量值
• 测量模式有3种
• 1.EXACTLY（精确值）:100dp,match_parent
• 2.AT_MOST:wrap_content
• 3.UNSPCIFIED:子控件想要多大就多大，不常用
• 
  
  • ViewGroup - LayoutParams
• FlowLayout - MarginLayoutParams
• 子View.getLayoutParams(); —–> LinearLayout.LayoutParams
  *
• 3重写onLayout();设置子View的位置

4FlowLayout继承ViewGroup实现流式布局

package com.imooc.view;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
/**
 * 思路
 * 1自定义ViewGrounp,写一个类继承ViewGrounp
 * 2重写onMeasure();测量子View的宽高，设置自己的宽高；
 *  onMeasure()根据子View的布局文件，为子View设置测量模式和测量值
 *  测量=测量模式+测量值
 *  测量模式有3种
 *  1.EXACTLY（精确值）:100dp,match_parent
 *  2.AT_MOST:wrap_content
 *  3.UNSPCIFIED:子控件想要多大就多大，不常用
 *
 *  ViewGroup - LayoutParams
 *  FlowLayout - MarginLayoutParams
 *  子View.getLayoutParams(); -----> LinearLayout.LayoutParams
 *
 * 3重写onLayout();设置子View的位置
 */
public class FlowLayout extends ViewGroup
{

    public FlowLayout(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        //
    }

    public FlowLayout(Context context, AttributeSet attrs)
    {
        this(context, attrs, 0);
    }

    public FlowLayout(Context context)
    {
        this(context, null);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

        // wrap_content
        int width = 0;
        int height = 0;

        // 记录每一行的宽度与高度
        int lineWidth = 0;
        int lineHeight = 0;

        // 得到内部元素的个数
        int cCount = getChildCount();

        for (int i = 0; i < cCount; i++)
        {
            View child = getChildAt(i);
            // 测量子View的宽和高
            measureChild(child, widthMeasureSpec, heightMeasureSpec);
            // 得到LayoutParams
            MarginLayoutParams lp = (MarginLayoutParams) child
                    .getLayoutParams();

            // 子View占据的宽度
            int childWidth = child.getMeasuredWidth() + lp.leftMargin
                    + lp.rightMargin;
            // 子View占据的高度
            int childHeight = child.getMeasuredHeight() + lp.topMargin
                    + lp.bottomMargin;

            // 换行
            if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight())
            {
                // 对比得到最大的宽度
                width = Math.max(width, lineWidth);
                // 重置lineWidth
                lineWidth = childWidth;
                // 记录行高
                height += lineHeight;
                lineHeight = childHeight;
            } else
            // 未换行
            {
                // 叠加行宽
                lineWidth += childWidth;
                // 得到当前行最大的高度
                lineHeight = Math.max(lineHeight, childHeight);
            }
            // 最后一个控件
            if (i == cCount - 1)
            {
                width = Math.max(lineWidth, width);
                height += lineHeight;
            }
        }

        Log.e("TAG", "sizeWidth = " + sizeWidth);
        Log.e("TAG", "sizeHeight = " + sizeHeight);

        setMeasuredDimension(
                //
                modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(),
                modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop()+ getPaddingBottom()//
        );

    }

    /**
     * 存储所有的View
     */
    private List<List<View>> mAllViews = new ArrayList<List<View>>();
    /**
     * 每一行的高度
     */
    private List<Integer> mLineHeight = new ArrayList<Integer>();

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b)
    {
        mAllViews.clear();
        mLineHeight.clear();

        // 当前ViewGroup的宽度
        int width = getWidth();

        int lineWidth = 0;
        int lineHeight = 0;

        List<View> lineViews = new ArrayList<View>();

        int cCount = getChildCount();

        for (int i = 0; i < cCount; i++)
        {
            View child = getChildAt(i);
            MarginLayoutParams lp = (MarginLayoutParams) child
                    .getLayoutParams();

            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            // 如果需要换行
            if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight())
            {
                // 记录LineHeight
                mLineHeight.add(lineHeight);
                // 记录当前行的Views
                mAllViews.add(lineViews);

                // 重置我们的行宽和行高
                lineWidth = 0;
                lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
                // 重置我们的View集合
                lineViews = new ArrayList<View>();
            }
            lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
            lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
                    + lp.bottomMargin);
            lineViews.add(child);

        }// for end
            // 处理最后一行
        mLineHeight.add(lineHeight);
        mAllViews.add(lineViews);

        // 设置子View的位置

        int left = getPaddingLeft();
        int top = getPaddingTop();

        // 行数
        int lineNum = mAllViews.size();

        for (int i = 0; i < lineNum; i++)
        {
            // 当前行的所有的View
            lineViews = mAllViews.get(i);
            lineHeight = mLineHeight.get(i);

            for (int j = 0; j < lineViews.size(); j++)
            {
                View child = lineViews.get(j);
                // 判断child的状态
                if (child.getVisibility() == View.GONE)
                {
                    continue;
                }

                MarginLayoutParams lp = (MarginLayoutParams) child
                        .getLayoutParams();

                int lc = left + lp.leftMargin;
                int tc = top + lp.topMargin;
                int rc = lc + child.getMeasuredWidth();
                int bc = tc + child.getMeasuredHeight();

                // 为子View进行布局
                child.layout(lc, tc, rc, bc);

                left += child.getMeasuredWidth() + lp.leftMargin
                        + lp.rightMargin;
            }
            left = getPaddingLeft() ; 
            top += lineHeight ; 
        }

    }

    /**
     * 与当前ViewGroup对应的LayoutParams
     */
    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs)
    {
        return new MarginLayoutParams(getContext(), attrs);
    }

}

5activity_main中使用

<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" >

    <com.imooc.view.FlowLayout
        android:padding="20dp"
        android:id="@+id/id_flowlayout"
        android:layout_width="fill_parent"
        android:background="#E5E5F5"
        android:layout_height="wrap_content" >

    </com.imooc.view.FlowLayout>

</RelativeLayout>

6在MainActivity中添加数据

package com.imooc.flowlayout;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.imooc.view.FlowLayout;

public class MainActivity extends Activity
{
    private String[] mVals = new String[]
    { "Hello", "Android", "Weclome Hi ", "Button", "TextView", "Hello",
            "Android", "Weclome", "Button ImageView", "TextView", "Helloworld",
            "Android", "Weclome Hello", "Button Text", "TextView" };

    private FlowLayout mFlowLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mFlowLayout = (FlowLayout) findViewById(R.id.id_flowlayout);

        initData();
    }

    public void initData()
    {
        // for (int i = 0; i < mVals.length; i++)
        // {
        // Button btn = new Button(this);
        //
        // MarginLayoutParams lp = new MarginLayoutParams(
        // MarginLayoutParams.WRAP_CONTENT,
        // MarginLayoutParams.WRAP_CONTENT);
        //
        // btn.setText(mVals[i]);
        // mFlowLayout.addView(btn, lp);
        // }
        LayoutInflater mInflater = LayoutInflater.from(this);
        for (int i = 0; i < mVals.length; i++)
        {
            TextView tv = (TextView) mInflater.inflate(R.layout.textlayout,
                    mFlowLayout, false);
            tv.setText(mVals[i]);
            mFlowLayout.addView(tv);
//          点击事件
            if(tv.getText().equals("Hello")) {
                tv.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Toast.makeText(MainActivity.this, "Hello", Toast.LENGTH_SHORT).show();
                    }
                });
            }
            if(tv.getText().equals("Android")) {
                tv.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Toast.makeText(MainActivity.this, "Android", Toast.LENGTH_SHORT).show();
                    }
                });

            }



        }

    }

}

7textlayout布局中给TextView添加背景

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:background="@drawable/tv_bg"
    android:textColor="#5BC4ED"
    android:text="Helloworld" >

</TextView>

8背景样式tv_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="#ffffff" />
    <corners android:radius="30dp" />
    <padding
        android:bottom="2dp"
        android:left="10dp"
        android:right="10dp"
        android:top="2dp" />
</shape>

源码下载：
https://download.csdn.net/download/zhaihaohao1/10564655
参考视频：
http://www.imooc.com/learn/237