本节引言:
在上一节结束后意味着Android的四大组件我们都已经学习完毕了~,而本节我们要学习的是四大组件间的枢纽——Intent(意图),Android通信的桥梁,比如我们可以通过:
- startActivity(Intent)/startActivityForResult(Intent):来启动一个Activity
- startService(Intent)/bindService(Intent):来启动一个Service
- sendBroadcast:发送广播到指定BroadcastReceiver
- 另外别忘了我们在注册四大组件时,写得很多的Intent-Filter哦~
好吧,话不多说,开始本节内容!另外前面我们已经用过Intent了,就不在讲述概念性的东西了~老规矩,官方API:Intent
1.显式Intent与隐式Intent的区别
- 显式Intent:通过组件名指定启动的目标组件,比如startActivity(new Intent(A.this,B.class));每次启动的组件只有一个~
- 隐式Intent:不指定组件名,而指定Intent的Action,Data,或Category,当我们启动组件时,会去匹配AndroidManifest.xml相关组件的Intent-filter,逐一匹配出满足属性的组件,当不止一个满足时,会弹出一个让我们选择启动哪个的对话框~
2.Intent的七个属性:
1)ComponentName(组件名称)
2)Action(动作)
3)Category(类别)
4)Data(数据),Type(MIME类型)
5)Extras(额外)
6)Flags(标记)
3.显式Intent使用示例:
这个用得很多,直接就上例子了:
例子1:点击按钮返回Home界面:运行效果图:
核心代码:
Intent it = new Intent();it.setAction(Intent.ACTION_MAIN);it.addCategory(Intent.CATEGORY_HOME);startActivity(it);
例子2:点击按钮打开百度页面:运行效果图:
核心代码:
Intent it = new Intent();it.setAction(Intent.ACTION_VIEW);it.setData(Uri.parse("https://www.baidu.com"));startActivity(it);
4.隐式Intent详解
1)预定义动作的隐式Intent示例:
代码示例:点击按钮后,所有Action为VIEW的Activity被筛选出来,由用户进一步选择:
核心代码:
建立第二个Activity的布局,与对应的Activity,在第一个Activity的按钮点击事件中添加一下代码:
Intent it = new Intent();it.setAction(Intent.ACTION_VIEW);startActivity(it);
最后在第二个Activity的Intent中添加以下代码:
<activity android:name=".SecondActivity" android:label="第二个Activity"> <intent-filter> <action android:name="android.intent.action.VIEW"/> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> </activity>
运行效果图:
2)自定义动作的隐式Intent示例:
代码示例:使用自定义的Action与category来激活另一个Activity
核心代码:建立第二个Activity的布局,与对应的Activity,在第一个Activity的按钮点击事件中添加一下代码:
Intent it = new Intent();it.setAction("my_action");it.addCategory("my_category");startActivity(it);
最后在第二个Activity的Intent中添加以下代码:
<activity android:name=".SecondActivity" android:label="第二个Activity"> <intent-filter> <action android:name="my_action"/> <category android:name="my_category"/> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> </activity>
注意虽然我们自定义了一个category,但是还是要把这个默认的加上,不然会报错的:
<category android:name="android.intent.category.DEFAULT"/>
5.常用系统Intent合集
大家贴下常用的系统Intent的合集吧,上面没有的欢迎提出~
//===============================================================//1.拨打电话// 给移动客服10086拨打电话Uri uri = Uri.parse("tel:10086");Intent intent = new Intent(Intent.ACTION_DIAL, uri);startActivity(intent);//===============================================================//2.发送短信// 给10086发送内容为“Hello”的短信Uri uri = Uri.parse("smsto:10086");Intent intent = new Intent(Intent.ACTION_SENDTO, uri);intent.putExtra("sms_body", "Hello");startActivity(intent);//3.发送彩信(相当于发送带附件的短信)Intent intent = new Intent(Intent.ACTION_SEND);intent.putExtra("sms_body", "Hello");Uri uri = Uri.parse("content://media/external/images/media/23");intent.putExtra(Intent.EXTRA_STREAM, uri);intent.setType("image/png");startActivity(intent);//===============================================================//4.打开浏览器:// 打开百度主页Uri uri = Uri.parse("https://www.baidu.com");Intent intent = new Intent(Intent.ACTION_VIEW, uri);startActivity(intent);//===============================================================//5.发送电子邮件:(阉割了Google服务的没戏!!!!)// 给someone@domain.com发邮件Uri uri = Uri.parse("mailto:someone@domain.com");Intent intent = new Intent(Intent.ACTION_SENDTO, uri);startActivity(intent);// 给someone@domain.com发邮件发送内容为“Hello”的邮件Intent intent = new Intent(Intent.ACTION_SEND);intent.putExtra(Intent.EXTRA_EMAIL, "someone@domain.com");intent.putExtra(Intent.EXTRA_SUBJECT, "Subject");intent.putExtra(Intent.EXTRA_TEXT, "Hello");intent.setType("text/plain");startActivity(intent);// 给多人发邮件Intent intent=new Intent(Intent.ACTION_SEND);String[] tos = {"1@abc.com", "2@abc.com"}; // 收件人String[] ccs = {"3@abc.com", "4@abc.com"}; // 抄送String[] bccs = {"5@abc.com", "6@abc.com"}; // 密送intent.putExtra(Intent.EXTRA_EMAIL, tos);intent.putExtra(Intent.EXTRA_CC, ccs);intent.putExtra(Intent.EXTRA_BCC, bccs);intent.putExtra(Intent.EXTRA_SUBJECT, "Subject");intent.putExtra(Intent.EXTRA_TEXT, "Hello");intent.setType("message/rfc822");startActivity(intent);//===============================================================//6.显示地图:// 打开Google地图中国北京位置(北纬39.9,东经116.3)Uri uri = Uri.parse("geo:39.9,116.3");Intent intent = new Intent(Intent.ACTION_VIEW, uri);startActivity(intent);//===============================================================//7.路径规划// 路径规划:从北京某地(北纬39.9,东经116.3)到上海某地(北纬31.2,东经121.4)Uri uri = Uri.parse("https://maps.google.com/maps?f=d&saddr=39.9 116.3&daddr=31.2 121.4");Intent intent = new Intent(Intent.ACTION_VIEW, uri);startActivity(intent);//===============================================================//8.多媒体播放:Intent intent = new Intent(Intent.ACTION_VIEW);Uri uri = Uri.parse("file:///sdcard/foo.mp3");intent.setDataAndType(uri, "audio/mp3");startActivity(intent);//获取SD卡下所有音频文件,然后播放第一首=-= Uri uri = Uri.withAppendedPath(MediaStore.Audio.Media.INTERNAL_CONTENT_URI, "1");Intent intent = new Intent(Intent.ACTION_VIEW, uri);startActivity(intent);//===============================================================//9.打开摄像头拍照:// 打开拍照程序Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); startActivityForResult(intent, 0);// 取出照片数据Bundle extras = intent.getExtras(); Bitmap bitmap = (Bitmap) extras.get("data");//另一种://调用系统相机应用程序,并存储拍下来的照片Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); time = Calendar.getInstance().getTimeInMillis();intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/tucue", time + ".jpg")));startActivityForResult(intent, ACTIVITY_GET_CAMERA_IMAGE);//===============================================================//10.获取并剪切图片// 获取并剪切图片Intent intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("image/*");intent.putExtra("crop", "true"); // 开启剪切intent.putExtra("aspectX", 1); // 剪切的宽高比为1:2intent.putExtra("aspectY", 2);intent.putExtra("outputX", 20); // 保存图片的宽和高intent.putExtra("outputY", 40); intent.putExtra("output", Uri.fromFile(new File("/mnt/sdcard/temp"))); // 保存路径intent.putExtra("outputFormat", "JPEG");// 返回格式startActivityForResult(intent, 0);// 剪切特定图片Intent intent = new Intent("com.android.camera.action.CROP"); intent.setClassName("com.android.camera", "com.android.camera.CropImage"); intent.setData(Uri.fromFile(new File("/mnt/sdcard/temp"))); intent.putExtra("outputX", 1); // 剪切的宽高比为1:2intent.putExtra("outputY", 2);intent.putExtra("aspectX", 20); // 保存图片的宽和高intent.putExtra("aspectY", 40);intent.putExtra("scale", true);intent.putExtra("noFaceDetection", true); intent.putExtra("output", Uri.parse("file:///mnt/sdcard/temp")); startActivityForResult(intent, 0);//===============================================================//11.打开Google Market // 打开Google Market直接进入该程序的详细页面Uri uri = Uri.parse("market://details?id=" + "com.demo.app");Intent intent = new Intent(Intent.ACTION_VIEW, uri);startActivity(intent);//===============================================================//12.进入手机设置界面:// 进入无线网络设置界面(其它可以举一反三) Intent intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS); startActivityForResult(intent, 0);//===============================================================//13.安装apk:Uri installUri = Uri.fromParts("package", "xxx", null); returnIt = new Intent(Intent.ACTION_PACKAGE_ADDED, installUri);//===============================================================//14.卸载apk:Uri uri = Uri.fromParts("package", strPackageName, null); Intent it = new Intent(Intent.ACTION_DELETE, uri); startActivity(it); //===============================================================//15.发送附件:Intent it = new Intent(Intent.ACTION_SEND); it.putExtra(Intent.EXTRA_SUBJECT, "The email subject text"); it.putExtra(Intent.EXTRA_STREAM, "file:///sdcard/eoe.mp3"); sendIntent.setType("audio/mp3"); startActivity(Intent.createChooser(it, "Choose Email Client"));//===============================================================//16.进入联系人页面:Intent intent = new Intent();intent.setAction(Intent.ACTION_VIEW);intent.setData(People.CONTENT_URI);startActivity(intent);//===============================================================//17.查看指定联系人:Uri personUri = ContentUris.withAppendedId(People.CONTENT_URI, info.id);//info.id联系人IDIntent intent = new Intent();intent.setAction(Intent.ACTION_VIEW);intent.setData(personUri);startActivity(intent);//===============================================================//18.调用系统编辑添加联系人(高版本SDK有效):Intent it = newIntent(Intent.ACTION_INSERT_OR_EDIT); it.setType("vnd.android.cursor.item/contact"); //it.setType(Contacts.CONTENT_ITEM_TYPE); it.putExtra("name","myName"); it.putExtra(android.provider.Contacts.Intents.Insert.COMPANY, "organization"); it.putExtra(android.provider.Contacts.Intents.Insert.EMAIL,"email"); it.putExtra(android.provider.Contacts.Intents.Insert.PHONE,"homePhone"); it.putExtra(android.provider.Contacts.Intents.Insert.SECONDARY_PHONE,"mobilePhone"); it.putExtra( android.provider.Contacts.Intents.Insert.TERTIARY_PHONE,"workPhone"); it.putExtra(android.provider.Contacts.Intents.Insert.JOB_TITLE,"title"); startActivity(it);//===============================================================//19.调用系统编辑添加联系人(全有效):Intent intent = newIntent(Intent.ACTION_INSERT_OR_EDIT); intent.setType(People.CONTENT_ITEM_TYPE); intent.putExtra(Contacts.Intents.Insert.NAME, "My Name"); intent.putExtra(Contacts.Intents.Insert.PHONE, "+1234567890"); intent.putExtra(Contacts.Intents.Insert.PHONE_TYPE,Contacts.PhonesColumns.TYPE_MOBILE); intent.putExtra(Contacts.Intents.Insert.EMAIL, "com@com.com"); intent.putExtra(Contacts.Intents.Insert.EMAIL_TYPE, Contacts.ContactMethodsColumns.TYPE_WORK); startActivity(intent);//===============================================================//20.打开另一程序 Intent i = new Intent(); ComponentName cn = new ComponentName("com.example.jay.test", "com.example.jay.test.MainActivity"); i.setComponent(cn); i.setAction("android.intent.action.MAIN"); startActivityForResult(i, RESULT_OK);//===============================================================//21.打开录音机Intent mi = new Intent(Media.RECORD_SOUND_ACTION); startActivity(mi);//===============================================================//22.从google搜索内容 Intent intent = new Intent(); intent.setAction(Intent.ACTION_WEB_SEARCH); intent.putExtra(SearchManager.QUERY,"searchString") startActivity(intent);//===============================================================
6.Action在哪里查?
本来想直接贴以前收集到的Intent Action的,后来想想还是算了,授之以鱼,还不如授之以渔,如果你下载了Android的文档的话,可以在下述路径:
sdk-->docs-->reference-->android--->content--->Intent.html
找到这个玩意,然后从这个Constants开始就是了:
遇到陌生的自己来这里查即可~
本节小结:
好的,关于Intent的基本使用就到这里,下一节我们会来继续学习在日常开发中使用Intent可能会遇到的一些问题或者说需求吧,敬请期待,谢谢~