1.模仿HOME键功能
Intent i= new Intent(Intent.ACTION_MAIN);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.addCategory(Intent.CATEGORY_HOME);
startActivity(i);
2.TextView中存取StringBuffer类型数据
TextView textView = findViewById(R.id.text);
StringBuffer a = new StringBuffer();
a.append("你好啊")；
存：textView.setText(a);
取：String result = textView.getText().toString().trim();----Wrong
String result = (String)textView.getText();-----OK
