Android 开发笔记___图像视图__简单截屏

 <?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">

     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="300dp"
         android:layout_marginTop="10dp"
         android:orientation="horizontal">

         <TextView
             android:id="@+id/tv_capture"
             android:layout_width="0dp"
             android:layout_height="match_parent"
             android:layout_weight="1"
             android:background="#ffffff"
             android:textColor="#000000"
             android:scrollbars="vertical"
             android:textSize="17sp" />

         <ImageView
             android:id="@+id/iv_capture"
             android:layout_width="0dp"
             android:layout_height="match_parent"
             android:layout_weight="1" />

     </LinearLayout>

     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_marginTop="10dp"
         android:orientation="horizontal">

         <Button
             android:id="@+id/btn_chat"
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="聊天"
             android:textColor="#000000"
             android:textSize="17sp" />

         <Button
             android:id="@+id/btn_capture"
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="截图"
             android:textColor="#000000"
             android:textSize="17sp" />

     </LinearLayout>

 </LinearLayout>

java

 package com.example.alimjan.hello_world;

 /**
  * Created by alimjan on 7/1/2017.
  */

 import android.content.Context;
 import android.content.Intent;
 import android.graphics.Bitmap;
         import android.os.Bundle;
         import android.os.Handler;
         import android.support.v7.app.AppCompatActivity;
 import android.text.method.ScrollingMovementMethod;
 import android.view.Gravity;
 import android.view.View;
         import android.widget.Button;
         import android.widget.ImageView;
         import android.widget.TextView;

 public class class__2_3_3_2 extends AppCompatActivity implements View.OnClickListener, View.OnLongClickListener {
     private TextView tv_capture;
     private ImageView iv_capture;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.code_2_3_3_2);
         tv_capture = (TextView) findViewById(R.id.tv_capture);
         iv_capture = (ImageView) findViewById(R.id.iv_capture);
         tv_capture.setDrawingCacheEnabled(true);
         tv_capture.setGravity(Gravity.LEFT|Gravity.BOTTOM);
         tv_capture.setLines(17);
         tv_capture.setMaxLines(17);
         tv_capture.setMovementMethod(new ScrollingMovementMethod());
         Button btn_chat = (Button) findViewById(R.id.btn_chat);
         Button btn_capture = (Button) findViewById(R.id.btn_capture);
         btn_chat.setOnClickListener(this);
         btn_chat.setOnLongClickListener(this);
         btn_capture.setOnClickListener(this);
     }

     private String[] mChatStr = { "你吃饭了吗？", "今天天气真好呀。",
             "我中奖啦！", "我们去看电影吧。", "晚上干什么好呢？" };

     @Override
     public boolean onLongClick(View v) {
         if (v.getId() == R.id.btn_chat) {
             tv_capture.setText("");
         }
         return true;
     }
     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btn_chat) {
             int random = (int)(Math.random()*10) % 5;
             String newStr = String.format("%s\n%s %s",
                     tv_capture.getText().toString(), DateUtil.getCurDateStr(), mChatStr[random]);
             tv_capture.setText(newStr);
         } else if (v.getId() == R.id.btn_capture) {
             Bitmap bitmap = tv_capture.getDrawingCache();
             iv_capture.setImageBitmap(bitmap);
             // 注意这里在截图完毕后不能马上关闭绘图缓存，因为画面渲染需要时间，
             // 如果立即关闭缓存，渲染画面就会找不到位图对象，会报错
             // “java.lang.IllegalArgumentException: Cannot draw recycled bitmaps”。
             mHandler.postDelayed(mResetCache, 200);
         }
     }

     private Handler mHandler = new Handler();
     private Runnable mResetCache = new Runnable() {
         @Override
         public void run() {
             tv_capture.setDrawingCacheEnabled(false);
             tv_capture.setDrawingCacheEnabled(true);
         }
     };

     public static void startHome(Context mContext) {
         Intent intent = new Intent(mContext, class__2_3_3_2.class);
         mContext.startActivity(intent);
     }
 }