更改 TextView 文本 [英] Change TextView text

问题描述

我正在尝试从代码中更改我的 TextView 文本.

I'm trying to change my TextView text from the code.

这就是我的 xml 的样子:

This is what my xml looks like:

XML:
<TextView
    android:id="@+id/textView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical|center_horizontal" />

还有代码:

TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
setContentView(tv1);

我的设备出现错误，应用程序停止.我试图显示一个 TextView(未连接到 XML TextView)并且它起作用了.

I'm getting an error on my device and the application stops. I tried to show a TextView (not connected to an XML TextView) and it worked.

推荐答案

你的方法不对.我认为这将是空指针异常(下次发布日志猫)

Your approach is incorrect. I think it will be Null Pointer Exception (next time post log cat)

在查找视图之前，您需要先指定要使用的布局.

You need to specify the layout you are using first, before finding views.

Java:

// Specify the layout you are using.
setContentView(R.layout.yourlayout);

// Load and use views afterwards
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");

科特林:

// Specify the layout you are using.
setContentView(R.layout.yourlayout)

// Load and use views afterwards
val tv1: TextView = findViewById(R.id.textView1)
tv1.text = "Hello"

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