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
%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);
    }
}