Android调用摄像头拍照开发教程

 package com.gyq.cameraalbumtest; import android.Manifest; import android.annotation.TargetApi; import android.content.ContentUris; import android.content.Intent; import android.content.pm.PackageManager; import android.database.Cursor; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.provider.DocumentsContract; import android.provider.MediaStore; import android.support.annotation.NonNull; 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.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; import java.io.File; public class MainActivity extends AppCompatActivity { public static final int TAKE_PHOTO = 1; public static final int CHOOSE_PHOTO = 2; private Button mTakePhoto, mChoosePhoto; private ImageView picture; private Uri imageUri; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mTakePhoto = (Button) findViewById(R.id.btn_take_photo); mChoosePhoto = (Button) findViewById(R.id.choose_from_album); picture = (ImageView) findViewById(R.id.iv_picture); mTakePhoto.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //创建file对象，用于存储拍照后的图片； File outputImage = new File(getExternalCacheDir(), "output_image.jpg-600"); try { if (outputImage.exists()) { outputImage.delete(); } outputImage.createNewFile(); } catch (Exception e) { e.printStackTrace(); } if (Build.VERSION.SDK_INT >= 24) { imageUri = FileProvider.getUriForFile(MainActivity.this, "com.gyq.cameraalbumtest.fileprovider", outputImage); } else { imageUri = Uri.fromFile(outputImage); } //启动相机程序 Intent intent = new Intent("android.media.action.IMAGE_CAPTURE"); intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); startActivityForResult(intent, TAKE_PHOTO); } }); mChoosePhoto.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1); } else { openAlbum(); } } }); } //打开相册 private void openAlbum() { Intent intent = new Intent("android.intent.action.GET_CONTENT"); intent.setType("image/*"); startActivityForResult(intent, CHOOSE_PHOTO); } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { switch (requestCode) { case 1: if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { openAlbum(); } else { Toast.makeText(this, "you denied the permission", Toast.LENGTH_SHORT).show(); } break; } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case TAKE_PHOTO: if (resultCode == RESULT_OK) { try { Bitmap bm = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri)); picture.setImageBitmap(bm); } catch (Exception e) { e.printStackTrace(); } } break; case CHOOSE_PHOTO: if (resultCode == RESULT_OK) { if (Build.VERSION.SDK_INT >= 19) { //4.4及以上的系统使用这个方法处理图片； handleImageOnKitKat(data); } else { handleImageBeforeKitKat(data); //4.4及以下的系统使用这个方法处理图片 } } default: break; } } private void handleImageBeforeKitKat(Intent data) { Uri uri = data.getData(); String imagePath = getImagePath(uri, null); displayImage(imagePath); } private String getImagePath(Uri uri, String selection) { String path = null; //通过Uri和selection来获取真实的图片路径 Cursor cursor = getContentResolver().query(uri, null, selection, null, null); if (cursor != null) { if (cursor.moveToFirst()) { path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA)); } cursor.close(); } return path; } private void displayImage(String imagePath) { if (imagePath != null) { Bitmap bitmap = BitmapFactory.decodeFile(imagePath); picture.setImageBitmap(bitmap); } else { Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show(); } } /** * 4.4及以上的系统使用这个方法处理图片 * * @param data */ @TargetApi(19) private void handleImageOnKitKat(Intent data) { String imagePath = null; Uri uri = data.getData(); if (DocumentsContract.isDocumentUri(this, uri)) { //如果document类型的Uri,则通过document来处理 String docID = DocumentsContract.getDocumentId(uri); if ("com.android.providers.media.documents".equals(uri.getAuthority())) { String id = docID.split(":")[1];   //解析出数字格式的id String selection = MediaStore.Images.Media._ID + "=" + id; imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection); } else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())) { Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/piblic_downloads"), Long.valueOf(docID)); imagePath = getImagePath(contentUri, null); } } else if ("content".equalsIgnoreCase(uri.getScheme())) { //如果是content类型的uri，则使用普通方式使用 imagePath = getImagePath(uri, null); } else if ("file".equalsIgnoreCase(uri.getScheme())) { //如果是file类型的uri，直接获取路径即可 imagePath = uri.getPath(); } displayImage(imagePath); } }