android 带EditView（编辑框）的AlertDialog（对话框）及获取输入内容

final EditText et = new EditText(this);
new AlertDialog.Builder(this).setTitle("搜索")
.setIcon(android.R.drawable.ic_dialog_info)
.setView(et)
.setPositiveButton("确定", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
String input = et.getText().toString();
if (input.equals("")) {
Toast.makeText(getApplicationContext(), "搜索内容不能为空！" + input, Toast.LENGTH_LONG).show();
}
else {
Intent intent = new Intent();
intent.putExtra("content", input);
intent.setClass(MainActivity.this, SearchActivity.class);
startActivity(intent);
}
}
})
.setNegativeButton("取消", null)
.show();