Activity的理解
Activity的运行状态分为
四种状态对应的生命周期流程图如下
Intent的理解如下
Intent的分类如下
IntentFilter的理解
Activity和Intent相关的API如下
Activity的Task Stack(任务栈)
特点：后进先出
Activity的LauchMode(加载模式)
具体详解看这篇文章
应用实例进行打电话与发短信，隐示意图的练习，代码如下
1、布局页面activity_intent_action.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".IntentActionActivity"> <LinearLayout android:id="@+id/linearLayout" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="电话号码:" android:textSize="15sp" /> <EditText android:id="@+id/edit_phone" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入电话号码" android:textSize="15sp" /> </LinearLayout> <LinearLayout android:id="@+id/linearLayout_message" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@id/linearLayout" android:orientation="horizontal"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="短信内容:" android:textSize="15sp" /> <EditText android:id="@+id/edit_message" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入短信内容" android:textSize="15sp" /> </LinearLayout> <Button android:id="@+id/btn_call" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/linearLayout_message" android:text="打电话" /> <Button android:id="@+id/btn_message" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/linearLayout_message" android:layout_toRightOf="@id/btn_call" android:text="发短信" /> </RelativeLayout>
2、在AndroidManifest.xml中声明打电话与发送短信的权限，这两个权限属于危险权限，还要在Java代码中动态申请。
<!-- 拨打电话的权限 --> <uses-permission android:name="android.permission.CALL_PHONE" /> <!--发送短信的权限--> <uses-permission android:name="android.permission.SEND_SMS" />
3、在IntentActionActivity类中进行具体代码的实现
public class IntentActionActivity extends AppCompatActivity implements View.OnClickListener, View.OnLongClickListener { private EditText edit_phone; private EditText edit_message; private Button btn_call; private Button btn_message; private static final int CALL_PHONE_CODE = 0X11; private static final int SEND_SMS_CODE = 0X22; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_intent_action); edit_phone = findViewById(R.id.edit_phone); edit_message = findViewById(R.id.edit_message); btn_call = findViewById(R.id.btn_call); btn_message = findViewById(R.id.btn_message); btn_call.setOnClickListener(this); btn_message.setOnClickListener(this); btn_call.setOnLongClickListener(this); btn_message.setOnLongClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.btn_call: //点击打电话 进入拨号的界面 //1.创建一个隐式意图Intent String action = "android.intent.action.DIAL"; // action=Intent.ACTION_DIAL;//一样的 Intent intent = new Intent(action); //2.携带数据 String number = edit_phone.getText().toString(); // <data android:scheme="tel"/> intent.setData(Uri.parse("tel:" + number)); startActivity(intent); break; case R.id.btn_message://点击发 短信进入编辑短信界面 Intent intent1 = new Intent(Intent.ACTION_SENDTO); //携带号码和内容 String numbers = edit_phone.getText().toString(); String sms = edit_message.getText().toString(); intent1.setData(Uri.parse("smsto:" + numbers)); intent1.putExtra("sms_body", sms); startActivity(intent1); break; default: break; } } @Override public boolean onLongClick(View v) { switch (v.getId()) { case R.id.btn_call: //长按打电话进入打电话的界面 //请求打电话的权限并打电话 RequestPermission(CALL_PHONE_CODE); break; case R.id.btn_message://长按发送短信 //请求发信息的权限并 发送短信信息 RequestPermission(SEND_SMS_CODE); break; default: break; } return true; } public void CallPage() { String action = "android.intent.action.CALL"; Intent intent = new Intent(action); //2.携带数据 String number = edit_phone.getText().toString(); intent.setData(Uri.parse("tel:" + number)); startActivity(intent); } public void sendText() { //1.得到SmsManager的对象 SmsManager smsManager = SmsManager.getDefault(); //2.发送文本信息(短信) String message = edit_message.getText().toString(); String phone = edit_phone.getText().toString(); smsManager.sendTextMessage(phone, null, message, null, null); } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { switch (requestCode) { case CALL_PHONE_CODE: CallPage(); break; case SEND_SMS_CODE: sendText(); break; default: break; } } else { switch (requestCode) { case CALL_PHONE_CODE: Toast.makeText(this, "打电话权限请求失败！", Toast.LENGTH_SHORT).show(); break; case SEND_SMS_CODE: Toast.makeText(this, "发送短信权限请求失败！", Toast.LENGTH_SHORT).show(); break; default: Toast.makeText(this, "测试！", Toast.LENGTH_SHORT).show(); break; } } } private void RequestPermission(int code) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { switch (code) { case CALL_PHONE_CODE: if (ContextCompat.checkSelfPermission(this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CALL_PHONE}, CALL_PHONE_CODE); } else { CallPage(); } break; case SEND_SMS_CODE: if (ContextCompat.checkSelfPermission(this, Manifest.permission.SEND_SMS) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.SEND_SMS}, SEND_SMS_CODE); } else { sendText(); } break; default: break; } } } }
总结
