android判断设备是否有相机的实例代码

PackageManager pm = getPackageManager();

// FEATURE_CAMERA - 后置相机

// FEATURE_CAMERA_FRONT - 前置相机

if(!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)

&& !pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)) {

    Log.i("camera","non-support");

}else{

    Log.i("camera","support");

}

<?xmlversion="1.0"encoding="utf-8"?>

<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"

  xmlns:tools="http://schemas.android.com/tools"

  android:id="@+id/activity_main"

  android:layout_width="match_parent"

  android:layout_height="match_parent"

  android:paddingBottom="@dimen/activity_vertical_margin"

  android:paddingLeft="@dimen/activity_horizontal_margin"

  android:paddingRight="@dimen/activity_horizontal_margin"

  android:paddingTop="@dimen/activity_vertical_margin"

  tools:context="com.itheima74.internetpicturelook.MainActivity">

  <EditText

    android:id="@+id/et_url"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:layout_alignParentLeft="true"

    android:layout_alignParentStart="true"

    android:layout_alignParentTop="true"

    android:hint="请输入图片网址"

    android:inputType="textUri"

    android:text="http://b.hiphotos.baidu.com/image/pic/item/d009b3de9c82d15825ffd75c840a19d8bd3e42da.jpg"/>

  <Button

    android:id="@+id/bt_look"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:layout_below="@+id/et_url"

    android:text="查看图片"/>

  <ScrollView

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_below="@+id/bt_look"

    android:layout_centerHorizontal="true">

    <ImageView

      android:id="@+id/iv"

      android:layout_width="wrap_content"

      android:layout_height="wrap_content"/>

  </ScrollView>

</RelativeLayout>

packagecom.itheima74.internetpicturelook;

importandroid.graphics.Bitmap;

importandroid.graphics.BitmapFactory;

importandroid.os.Bundle;

importandroid.support.v7.app.AppCompatActivity;

importandroid.view.View;

importandroid.widget.EditText;

importandroid.widget.ImageView;

importandroid.widget.Toast;

importjava.io.IOException;

importjava.io.InputStream;

importjava.net.HttpURLConnection;

importjava.net.URL;

publicclassMainActivityextendsAppCompatActivity {

  privateEditText et_url;

  privateImageView iv;

  @Override

  protectedvoidonCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    et_url = (EditText) findViewById(R.id.et_url);

    iv = (ImageView) findViewById(R.id.iv);

    findViewById(R.id.bt_look).setOnClickListener(newView.OnClickListener() {

      @Override

      publicvoidonClick(View v) {

        String path = et_url.getText().toString().trim();

        if(path.isEmpty()) {

          Toast.makeText(MainActivity.this,"请输入图片网址", Toast.LENGTH_SHORT).show();

        }else{

          //开启子线程去网络下载图片

          downLoadPicture(path);

        }

      }

      privatevoiddownLoadPicture(finalString path) {

        // 子线程请求网络

        newThread() {

          @Override

          publicvoidrun() {

            try{

              URL url =newURL(path);

              HttpURLConnection connection = (HttpURLConnection) url.openConnection();

              connection.setRequestMethod("GET");

              connection.setConnectTimeout(5000);

              intresponseCode = connection.getResponseCode();

              if(responseCode ==200) {

                InputStream inputStream = connection.getInputStream();

                finalBitmap bitmap = BitmapFactory.decodeStream(inputStream);

                // 主线程更新UI

                runOnUiThread(newRunnable() {

                  @Override

                  publicvoidrun() {

                    iv.setImageBitmap(bitmap);

                  }

                });

              }

            }catch(IOException e) {

              e.printStackTrace();

            }

          }

        }.start();

      }

    });

  }

}

/**

     *

     * 利用给定路径下的图片设置ImageView

     *

     * @param imgPath   手机图片文件路径

     * @param imgView   需要设置的ImageView

     */

publicvoidsetImg(String imgPath, ImageView imgView) {

        File file =newFile(imgPath);

        if(file.exists() && file.canRead()) {

            // -------1.图片缩放--------

            // 手机屏幕信息

            DisplayMetrics metric =newDisplayMetrics();

            getWindowManager().getDefaultDisplay().getMetrics(metric);

            intdw = metric.widthPixels;// 屏幕宽

            intdh = metric.heightPixels;// 屏幕高

            // 加载图像，只是为了获取尺寸

            BitmapFactory.Options options =newBitmapFactory.Options();

            options.inJustDecodeBounds =true;// 设置之后可以获取尺寸信息

            Bitmap bitmap = BitmapFactory.decodeFile(imgPath, options);

            // 计算水平和垂直缩放系数

            intheightRatio = (int) Math.ceil(options.outHeight / (float) dh);

            intwidthRatio = (int) Math.ceil(options.outWidth / (float) dw);

            // 判断哪个大

            if(heightRatio >1&& widthRatio >1) {

                if(heightRatio > widthRatio) {

                    options.inSampleSize = heightRatio;

                }else{

                    options.inSampleSize = widthRatio;

                }

            }

            // 图片缩放

            options.inJustDecodeBounds =false;

            bitmap = BitmapFactory.decodeFile(imgPath, options);

            // -------2.判断图片朝向--------

            try{

                ExifInterface exif =newExifInterface(imgPath);

                intdegree =0;// 图片旋转角度

                if(exif !=null) {

                    intorientation = exif.getAttributeInt(

                            ExifInterface.TAG_ORIENTATION, -1);

                    if(orientation != -1) {

                        switch(orientation) {

                        caseExifInterface.ORIENTATION_ROTATE_90:

                            degree =90;

                            break;

                        caseExifInterface.ORIENTATION_ROTATE_180:

                            degree =180;

                            break;

                        caseExifInterface.ORIENTATION_ROTATE_270:

                            degree =270;

                            break;

                        default:

                            break;

                        }

                    }

                }

                if(degree !=0) {// 图片需要旋转

                    intwidth = bitmap.getWidth();

                    intheight = bitmap.getHeight();

                    Matrix matrix =newMatrix();

                    matrix.preRotate(degree);

                    Bitmap mRotateBitmap = Bitmap.createBitmap(bitmap,0,0,

                            width, height, matrix,true);

                    imgView.setImageBitmap(mRotateBitmap);

                }else{

                    imgView.setImageBitmap(bitmap);

                }

            }catch(IOException e) {

            }

        }

    }