1.基础
Context context = getApplicationContext();
CharSequence text = "Hello toast!";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
当然也可以将方法连起来而不是保持一个Toast对象：
Toast.makeText(context, text, duration).show();
2.放置位置
toast.setGravity(Gravity.TOP|Gravity.LEFT, x, y);
可以通过setGravity方法来改变toast的默认显示位置
3.自定义Toast
LayoutInflater inflater = getLayoutInflater();
View layout = inflater.inflate(R.layout.custom_toast,
(ViewGroup) findViewById(R.id.toast_layout_root));
TextView text = (TextView) layout.findViewById(R.id.text);
text.setText("This is a custom toast");
Toast toast = new Toast(getApplicationContext());
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.setDuration(Toast.LENGTH_LONG);
toast.setView(layout);
toast.show();
