使用内置的Camera应用程序

古城微笑少年丶 2022-07-27 13:52 180阅读 0赞

![这里写图片描述][20160427000154871]  
该小节非常简单，讲的就三件事：  
一，调用Camera相机拍照并获取照片；  
二、调用Camera相机拍照并获得原图；  
三、获得原图后根据屏幕的宽高比来显示图片。  
调用Camera相机拍照并获取照片源码如下：  
package com.hhqy.withme;

import android.content.Intent;  
import android.graphics.Bitmap;  
import android.os.Bundle;  
import android.support.v4.app.FragmentActivity;  
import android.widget.ImageView;

public class ContextActivity extends FragmentActivity \{

private ImageView image;  
    
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_context);  
        image = (ImageView)findViewById(R.id.cursor);  
        Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        //android.provider.MediaStore.ACTION_IMAGE_CAPTURE
        //打开相机的意图
        startActivityForResult(intent, 100);
    
    }  
    
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent) 
    {
        super.onActivityResult(requestCode, resultCode, intent);
        if(requestCode == 100 && resultCode == RESULT_OK)
        {
            Bundle bundle = intent.getExtras();
            image.setImageBitmap((Bitmap)bundle.get("data"));
        }
    }

\}  
布局文件只有一个imageView控件，所以就不写了，后面一样！  
通过运行你会发现图片缩小了  
![这里写图片描述][20160426233023709]  
那如何获得原图大小呢？书中给的代码是这样的：  
package com.hhqy.withme;

import java.io.File;  
import java.util.ArrayList;

import android.content.Intent;  
import android.graphics.Bitmap;  
import android.graphics.BitmapFactory;  
import android.graphics.Matrix;  
import android.net.Uri;  
import android.os.Bundle;  
import android.os.Environment;  
import android.os.Handler;  
import android.os.Message;  
import android.support.v4.app.Fragment;  
import android.support.v4.app.FragmentActivity;  
import android.support.v4.view.ViewPager;  
import android.support.v4.view.ViewPager.OnPageChangeListener;  
import android.util.DisplayMetrics;  
import android.util.Log;  
import android.view.Display;  
import android.view.Menu;  
import android.view.View;  
import android.view.animation.Animation;  
import android.view.animation.TranslateAnimation;  
import android.widget.ImageView;  
import android.widget.TextView;  
import android.widget.Toast;

public class ContextActivity extends FragmentActivity \{

private ImageView image;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_context);  
        image = (ImageView)findViewById(R.id.cursor);  
        String path = Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg";
        Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(path)));
        //也可这样写uri:Uri.parse("file:///sdcard/hello.jpg")，但是上一种更规范一些
        startActivityForResult(intent, 100);
    }  
    
    
    @Override
    protected void onActivityResult(int arg0, int arg1, Intent arg2) 
    {
        super.onActivityResult(arg0, arg1, arg2);
        if(arg1 == RESULT_OK)
        {
            Bundle bundle = arg2.getExtras();
            image.setImageBitmap((Bitmap)bundle.get("data"));
    
        }
    }

\}  
但是一运行的时候，你会发现拿不到图片了！！  
![这里写图片描述][20160426233942503]  
后来上网查询了一下，我们可以通过文件名来获取，直接取是取不到了，修改一小段：  
@Override  
protected void onActivityResult(int arg0, int arg1, Intent arg2)  
\{  
super.onActivityResult(arg0, arg1, arg2);  
if(arg1 == RESULT\_OK)  
\{  
Bundle bundle = arg2.getExtras();  
image.setImageBitmap((Bitmap)bundle.get(“data”));

BitmapFactory.Options option = new BitmapFactory.Options();
            option.inJustDecodeBounds = false;
            Bitmap bitmapTure = BitmapFactory.decodeFile(
                    Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",
                    option);
            image.setImageBitmap(bitmapTure);
    
        }
    }
    ![这里还是不行，具体原因我也不知道了，或许是时间的原因请知道的朋友指教！最后还是贴上能运行的代码：](https://img-blog.csdn.net/20160426235309571)
    效果大家可以自己试一下，我只是随手拍的！
    最后，图片太大了，如何根据屏幕的宽高比来显示图片呢？不说话，上源码：
    package com.hhqy.withme;

import android.content.Intent;  
import android.graphics.Bitmap;  
import android.graphics.BitmapFactory;  
import android.net.Uri;  
import android.os.Bundle;  
import android.os.Environment;  
import android.support.v4.app.FragmentActivity;  
import android.view.Display;  
import android.widget.ImageView;

public class ContextActivity extends FragmentActivity \{

private ImageView image;  
    
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_context);  
        image = (ImageView)findViewById(R.id.cursor);  
        String path = Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg";
        Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, Uri.parse("file:///sdcard/hello.jpg"));
        startActivityForResult(intent, 100);
    }  
    
    
    @Override
    protected void onActivityResult(int arg0, int arg1, Intent arg2) 
    {
        super.onActivityResult(arg0, arg1, arg2);
        if(arg1 == RESULT_OK)
        {

// Bundle bundle = arg2.getExtras();  
// image.setImageBitmap((Bitmap)bundle.get(“data”));  
Display display = getWindowManager().getDefaultDisplay();  
int dw = display.getWidth();//窗口宽度  
int dh = display.getHeight();//窗口高度

BitmapFactory.Options option = new BitmapFactory.Options();
            option.inJustDecodeBounds = true;//只加载图像尺寸，而不用加载图像本身，例如只问参加活动的人数，而不问具体哪些人参加一样！
            Bitmap bitmapFalse = BitmapFactory.decodeFile(
                    Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",
                    option);
            int hRatio = (int) Math.ceil(option.outHeight/dh);
            int wRatio = (int) Math.ceil(option.outWidth/dw);
            if(hRatio>1 && wRatio>1)
            {
                if(hRatio>wRatio)
                {
                    option.inSampleSize = hRatio;
    
                }else 
                {
                    option.inSampleSize = wRatio;
                }
            }
            option.inJustDecodeBounds = false;
            Bitmap bitmapTure = BitmapFactory.decodeFile(
                    Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",
                    option);
            image.setImageBitmap(bitmapTure);

// ContentResolver c = this.getContentResolver();  
// try \{  
// Bitmap bmp = BitmapFactory.decodeStream(c.openInputStream(Uri.parse(“file:///sdcard/hello.jpg”)));  
// if(bmp!=null)image.setImageBitmap(bmp);  
// \} catch (FileNotFoundException e) \{  
// Toast.makeText(this, “图片取出来有问题”, Toast.LENGTH\_SHORT).show();  
// e.printStackTrace();  
// \}  
\}  
\}

![这里写图片描述][20160427000728029]

![这里写图片描述][20160427000816155]  
重点不是我照片拍的丑，重点是技术的实现和熟练，欢迎大家交流：QQ3332168769  
（我至今也不明白为什么给了一个uri之后为什么会取不出来图片这个问题，求指教！！！）

[20160427000154871]: /images/20220727/4dbad18714b5466bac591622cca976a3.png
[20160426233023709]: /images/20220727/0ac4bc56806643df946c666d90f9a4b5.png
[20160426233942503]: /images/20220727/448649e72bdc400da0b61ae56458d855.png
[20160427000728029]: /images/20220727/247c564ea0e4403489a81b1afb5b583a.png
[20160427000816155]: /images/20220727/286a194240e34dfba7c75032ba7bbbe0.png