Android新手开发之旅-流式布局实现热门标签

liu

Android新手开发之旅目录



第一步：自定义view继承ViewGroup

[Java] 纯文本查看 复制代码

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

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

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);

        // 如果是warp_content情况下，记录宽和高
        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++) {
            // 通过索引拿到每一个子view
            View child = getChildAt(i);
            // 测量子View的宽和高,系统提供的measureChild
            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 判断 当前的宽度大于 开辟新行
            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);
            }
            // 特殊情况,最后一个控件
            if (i == cCount - 1) {
                width = Math.max(lineWidth, width);
                height += lineHeight;
            }
        }
        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;

        // 存放每一行的子view
        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);
    }



}

第二步：在布局中使用自定义的view

[XML] 纯文本查看 复制代码

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

    <com.company.test.FlowLayout
        android:id="@+id/fl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

第三步:每个item的布局

[XML] 纯文本查看 复制代码

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/tv_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="5dp"
    android:layout_margin="8dp"
    android:padding="5dp"
    android:background="@drawable/bg_flowlayout"
    android:textColor="@color/colorPrimary"
    android:textSize="14sp" />

bg_flowlayout:

[XML] 纯文本查看 复制代码

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="3dp" />
    <stroke
        android:width="0.5dp"
        android:color="@color/colorPrimary" />
</shape>

第四步：

[Java] 纯文本查看 复制代码

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private FlowLayout mFlowLayout;
    private String[] data = {"Java", "Android", "Ios", "前端", "C++", "软件工程师","高级工程师","数据库开发","项目经理","美工","PHP","数据分析","网络工程师","网站编辑","Go"};

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

        initView();
    }

    private void initView() {
        mFlowLayout = (FlowLayout) findViewById(R.id.fl);
        for (int i = 0; i < data.length; i++) {
            TextView tv = (TextView) LayoutInflater.from(this).inflate(R.layout.item_flowlayout, mFlowLayout, false);
            tv.setText(data[i]);
            mFlowLayout.addView(tv);
            final int finalI = i;
            tv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(MainActivity.this, "你点击了" + data[finalI], Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

}

运行效果：

              

站长苏飞

我只是路过打酱油的。

竹林风

真是难得给力的帖子啊。

范范

我只是路过打酱油的。

惜

激动人心，无法言表！

Amy

强烈支持楼主ing……