android调用相机

xml文件:

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

    <Button
        android:id="@+id/take_photo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="take photo"
        android:textAllCaps="false"/>
    <Button
        android:id="@+id/take_photo2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="take photo2"
        android:textAllCaps="false"/>

    <ImageView
        android:id="@+id/pic"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

activity:

package com.example.myapplication;

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
import android.hardware.Camera;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.StrictMode;
import android.provider.MediaStore;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URL;

/**
 * Created by 刘入贵 on 2019/8/17.
 */

public class Camer extends AppCompatActivity {

    public static String TAG="Camer.this";
    private int Result_1=1;
    private int Result_2=2;
    private ImageView pic;
    private String mfilepath;
    private Button btn1;//take photo
    private Button btn2;//take photo2


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

        Button takephoto = (Button) findViewById(R.id.take_photo);
        pic= (ImageView) findViewById(R.id.pic);;


        //动态申请权限
        int cameraPermission = ContextCompat.checkSelfPermission(Camer.this, Manifest.permission.CAMERA);
        if (cameraPermission != PackageManager.PERMISSION_GRANTED) {
            String[] PERMISSIONS_CAMERA_AND_STORAGE = {
                    Manifest.permission.READ_EXTERNAL_STORAGE,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE,
                    Manifest.permission.CAMERA};
            ActivityCompat.requestPermissions(Camer.this, PERMISSIONS_CAMERA_AND_STORAGE, 0x001);
        }
        
        // android 7.0系统解决拍照的问题
        StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
        StrictMode.setVmPolicy(builder.build());
        builder.detectFileUriExposure();

        //图片保存路径
        mfilepath= Environment.getExternalStorageDirectory().getPath();
        mfilepath=mfilepath+"/"+"temp.png";

        btn1= (Button) findViewById(R.id.take_photo);
        btn2= (Button) findViewById(R.id.take_photo2);

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openCamera();
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openCamera2();
            }
        });




    }

    //隐式调用intent,返回图片缩略图
    private void openCamera() {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(intent,Result_1);
    }
    //第二种方式
    public void openCamera2(){
        Intent intent=new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        Uri photourl=Uri.fromFile(new File(mfilepath));
        intent.putExtra(MediaStore.EXTRA_OUTPUT,photourl);
        startActivityForResult(intent,Result_2);
    }

    //Intent调用的返回结果
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            if (requestCode == Result_1) {
                Bundle bundle = data.getExtras();
                Bitmap bitmap = (Bitmap) bundle.get("data");
                pic.setImageBitmap(bitmap);
            }else if (requestCode==Result_2){
                FileInputStream fis=null;
                try {
                    fis=new FileInputStream(mfilepath);
                    Bitmap bitmap=BitmapFactory.decodeStream(fis);
                    pic.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }finally {
                    try {
                        fis.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

    }
}

 

### 调用相机API实现拍照功能 #### 权限声明 为了能够在应用程序中使用相机,必须在`AndroidManifest.xml`文件中声明必要的权限。对于访问相机硬件而言,需要声明`CAMERA`权限;如果还需要读取或写入外部存储,则需额外声明相应的权限[^3]。 ```xml <uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> ``` #### 动态请求权限 自Android 6.0 (API level 23)起,在运行时动态获取用户授予敏感权限变得必要。这意味着即使已经在manifest里定义好了所需权限,也得通过代码向用户申请这些权限才能正常使用相应特性。 ```java if (ContextCompat.checkSelfPermission(thisActivity, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(thisActivity, new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA); } ``` #### 创建Intent启动相机应用 当获得了所需的权限之后,就可以构建一个带有特定动作(`IMAGE_CAPTURE`)的Intent对象,并利用startActivityForResult()方法触发默认相机界面让用户完成拍摄操作[^2]。 ```java private static final int REQUEST_IMAGE_CAPTURE = 1; // ... Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); try { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE); } catch (ActivityNotFoundException e) { // Handle exception when no camera app is available. } ``` #### 处理返回的数据 一旦用户完成了图片捕捉并关闭了相机activity,系统会回调onActivityResult()函数传递回所拍下的照片数据给开发者处理。 ```java @Override protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK){ Bundle extras = data.getExtras(); Bitmap imageBitmap = (Bitmap) extras.get("data"); // Do something with the captured photo... } } ```
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