Android TextView的使用方法

Android中的TextView对应VC、VB中的Label。

1. 最简单的情形：显示一个TextView

1.1 布局文件 activit_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<TextView
android:id="@+id/text_view_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/text_view_default_value" />

</LinearLayout>

1.2 字符串资源文件

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">HelloTextView</string>
<string name="action_settings">Settings</string>
<string name="text_view_default_value">Hello TextView</string>
</resources>

1.3 代码

package com.example.hellotextview;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);
TextView textView = (TextView)this.findViewById(R.id.text_view_id);
}

}

1.4 运行结果

2. 动态修改TextView的文本

2.1 代码

启动HelloTextView应用之后，通过Home键来回隐藏/显示这个应用。而每次显示的时候，循环地显示几个字符串。

package com.example.hellotextview;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class MainActivity extends Activity {
private static final String TAG = "MainActivity";

TextView textView = null;

private List<String> values = new ArrayList<String>();
private int count = 0;
private int index = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

values.add("Shanghai");
values.add("Beijing");
values.add("Others");
count = values.size();
index = 0;

setContentView(R.layout.activity_main);
textView = (TextView)this.findViewById(R.id.text_view_id);
}

protected void onResume() {
super.onResume();

textView.setText(values.get(index));
Log.d(TAG, "index=" + index + ",text=" + textView.getText());
index = (index + 1) % count;
}

}

2.2 运行结果

3. 响应按键事件OnClickListener()

现在增加事件处理，即当单击TextView对象的时候，就更新文本串。

3.1 代码

package com.example.hellotextview;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;

public class MainActivity extends Activity {
private static final String TAG = "MainActivity";

TextView textView = null;

private List<String> values = new ArrayList<String>();
private int count = 0;
private int index = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

values.add("Shanghai");
values.add("Beijing");
values.add("Others");
count = values.size();
index = 0;

setContentView(R.layout.activity_main);
textView = (TextView)this.findViewById(R.id.text_view_id);
Log.d(TAG, "index=" + index + ",text=" + textView.getText());

textView.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
textView.setText(values.get(index));
Log.d(TAG, "index=" + index + ",text=" + textView.getText());
index = (index + 1) % count;
}

});
}

protected void onResume() {
super.onResume();
}

}

3.2 运行结果