Android可收缩/扩展的TextView【2】

Android可收缩/扩展的TextView【2】

我写的可扩展/收缩的TextView：PhilExpandableTextView使用方法在附录文章1中已经说明。简单的使用，可以直接写在布局中，初始默认是收缩成3行（可修改继续定制），当用户从触发expand事件后，PhilExpandableTextView将伸展成完全的行数。
PhilExpandableTextView在ListView一类的使用中，有些特殊，现在以PhilExpandableTextView在Android RecyclerView中的使用为例加以说明。
测试的主Activity MainActivity.java:

package zhangphil.text;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends Activity {

	private ArrayList<Boolean> flags;

	private MyRecyclerViewAdapter adapter;
	private String test_str = "";

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

		// 测试的字符串
		for (int i = 0; i < 100; i++)
			test_str = test_str + " " + i;

		setContentView(R.layout.activity_main);

		RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);

		LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
		mLayoutManager.setOrientation(LinearLayout.VERTICAL);
		mRecyclerView.setLayoutManager(mLayoutManager);

		adapter = new MyRecyclerViewAdapter(this);

		mRecyclerView.setAdapter(adapter);
	}

	private class MyViewHolder extends RecyclerView.ViewHolder {

		private PhilExpandableTextView text;
		private Button button;

		public MyViewHolder(View itemView) {
			super(itemView);

			text = (PhilExpandableTextView) itemView.findViewById(R.id.textView);
			button = (Button) itemView.findViewById(R.id.button);
		}
	}

	private class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyViewHolder> {

		private LayoutInflater inflater;

		public MyRecyclerViewAdapter(Context context) {
			inflater = LayoutInflater.from(context);

			flags = new ArrayList<Boolean>();
			for (int i = 0; i < this.getItemCount(); i++) {
				flags.add(false);
			}
		}

		@Override
		public int getItemCount() {
			return 100;
		}

		@Override
		public void onBindViewHolder(MyViewHolder holder, final int pos) {

			holder.text.setText("position:" + pos + " -> " + test_str);

			holder.button.setOnClickListener(new View.OnClickListener() {

				@Override
				public void onClick(View v) {
					boolean b = flags.get(pos);
					b = !b;
					flags.set(pos, b);

					adapter.notifyDataSetChanged();
				}
			});

			boolean b = flags.get(pos);
			holder.text.setExpandable(b);

			String s = "";
			if (b)
				s = "收缩 " + pos;
			else
				s = "展开 " + pos;

			holder.button.setText(s);
		}

		@Override
		public MyViewHolder onCreateViewHolder(ViewGroup group, int pos) {
			View v = inflater.inflate(R.layout.item, null);
			MyViewHolder holder = new MyViewHolder(v);
			return holder;
		}
	}
}

MainActivity.java需要的布局文件：

<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="zhangphil.text.MainActivity" >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:divider="#ff5252"
        android:dividerHeight="10dip"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

item.xml布局文件：

<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="wrap_content"
    android:layout_margin="5dip"
    android:background="@android:color/white"
    tools:context="zhangphil.text.MainActivity" >

    <zhangphil.text.PhilExpandableTextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dip"
        android:background="#03a9f4"
        android:textColor="@android:color/white" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/textView"
        android:text="展开" />
</RelativeLayout>

我写的PhilExpandableTextView.java：

package zhangphil.text;

import android.content.Context;
import android.util.AttributeSet;
import android.view.ViewTreeObserver;
import android.widget.TextView;

public class PhilExpandableTextView extends TextView {

	// 最大的行，默认只显示3行
	private final int MAX = 3;

	// 如果完全伸展需要多少行？
	private int lines;

	private PhilExpandableTextView mPhilTextView;

	// 标记当前TextView的展开/收缩状态
	// true，已经展开
	// false，以及收缩
	private boolean expandableStatus = false;

	public PhilExpandableTextView(Context context, AttributeSet attrs) {
		super(context, attrs);

		mPhilTextView = this;

		init();
	}

	private void init() {

		// ViewTreeObserver View观察者，在View即将绘制但还未绘制的时候执行的，在onDraw之前
		final ViewTreeObserver mViewTreeObserver = this.getViewTreeObserver();

		mViewTreeObserver.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

			@Override
			public boolean onPreDraw() {
				// 避免重复监听
				mPhilTextView.getViewTreeObserver().removeOnPreDrawListener(this);

				lines = getLineCount();
				// Log.d(this.getClass().getName(), lines+"");

				return true;
			}
		});

		setMaxLines(MAX);
		
		//setEllipsize(TextUtils.TruncateAt.END);
	}

	// 是否展开或者收缩，
	// true，展开；
	// false，不展开
	public void setExpandable(boolean isExpand) {
		if (isExpand) {
			setMaxLines(lines + 1);
		} else
			setMaxLines(MAX);

		expandableStatus = isExpand;
	}

	public boolean getExpandableStatus() {
		return expandableStatus;
	}
}

代码运行结果：

附录我写的相关文章：
【文章1】《Android可收缩/扩展的TextView【1】》链接地址：http://blog.csdn.net/zhangphil/article/details/50088465