打开activity的方法有哪些

打开activity的方法有以下几种：
1. 使用显式Intent打开目标Activity：
```java
Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
startActivity(intent);
```
2. 使用隐式Intent打开目标Activity：
```java
Intent intent = new Intent();
intent.setAction("com.example.ACTION_TARGET_ACTIVITY");
startActivity(intent);
```
3. 使用Intent传递数据到目标Activity：
```java
Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
intent.putExtra("key", value);
startActivity(intent);
```
4. 使用startActivityForResult()方法打开目标Activity，并获取返回结果：
```java
Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
startActivityForResult(intent, REQUEST_CODE);
```
5. 使用FLAG_ACTIVITY_NEW_TASK标记打开目标Activity：
```java
Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
```
6. 使用PendingIntent打开目标Activity：
```java
Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(CurrentActivity.this, requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
pendingIntent.send();
```