android练习之定制toast消息位置

这个练习需要你定制toast消息，改在屏幕顶部而不是底部显示弹出消息。这需要使用Toast 类的setGravity方法，并使用Gravity.TOP重力值。

activity_quiz.xml代码

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="24dp"
        android:text="@string/question_text"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/trueBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/true_button"/>

        <Button
            android:id="@+id/falseBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/false_button"/>
    </LinearLayout>
</LinearLayout>

QuizActivity代码

package com.example.jarvis.geoquiz;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class QuizActivity extends AppCompatActivity {

    private Button mTrueButton;
    private Button mFalseButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_quiz);

        mTrueButton=(Button)findViewById(R.id.trueBtn);
        mFalseButton=(Button)findViewById(R.id.falseBtn);

        mTrueButton.setOnClickListener(new View.OnClickListener(){

            public void onClick(View v){
                Toast t=Toast.makeText(QuizActivity.this,
                        R.string.correct_toast,
                        Toast.LENGTH_SHORT);
                t.setGravity(Gravity.TOP,0,0);
                t.show();
            }
        });

        mFalseButton.setOnClickListener(new View.OnClickListener(){

            public void onClick(View v){
                Toast toast=Toast.makeText(QuizActivity.this,
                        R.string.incorrect_toast,
                        Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.CENTER,0,0);
                toast.show();
            }
        });
    }
}

效果图