基本上,这段代码的重点是用一种方式解释字符串,即正在创建的视图将被放置在前面提到的视图中。
% $- background:#000000 %
Hello, World.
% $- background:#ffffff %
$+ id:test type:container %
Test
下面是它的代码。
new Thread() {
StringBuilder text = new StringBuilder();
@Override
public void run() {
try
{
String str = "";
URL url = new URL("http://example.com/" + mes + "/" + mes + ".meb");
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
while ((str = in.readLine()) != null) {
text.append(str);
}
in.close();
} catch (MalformedURLException e1)
{
}
catch (IOException e)
{
}
if(message.contains(".meb")) {
String strn = text.toString().replace("n", "").replace("r", "");
String str[] = strn.toString().split("%");
int relative2 = 0;
final int relative = relative2;
for (final String l : str) {
String code[] = l.split(" ");
if (l.toString().contains("$-")) {
for(String p : code)
{
if(p.toString().contains("background"))
{
final String set[] = p.toString().split(":");
runOnUiThread(new Runnable() {
@Override
public void run() {
(findViewById(R.id.body)).setBackgroundColor(Color.parseColor(set[1]));
}
});
}
}
}
else if(l.toString().contains("$+"))
{
String[] g = code[2].split(":");
String[] c = code[3].split(":");
final String[] test = {g[1], "100"};
globvar.add(test);
if(c[1].toString().equals("container")) {
runOnUiThread(new Runnable() {
@Override
public void run() {
final LinearLayout element = new LinearLayout(getApplicationContext());
element.setBackgroundColor(Color.parseColor("#FFFFFF"));
element.setMinimumHeight(50);
element.setId(Integer.parseInt(test[1]));
((LinearLayout) findViewById(relative)).addView(element);
}
});
relative2 = Integer.parseInt(test[1]);
}
}
else {
if(!l.toString().isEmpty()) {
runOnUiThread(new Runnable() {
@Override
public void run() {
final TextView tv = new TextView(getApplicationContext());
tv.setTextColor(Color.parseColor("#000000"));
tv.setTextSize(18);
tv.setText(l);
((LinearLayout) findViewById(relative)).addView(tv);
}
});
}
}
}
}
else {
if(message == null) {
runOnUiThread(new Runnable() {
@Override
public void run() {
}
});
}
}
}
}.start();
应用程序崩溃时,我得到以下logcat错误:
08-01 19:44:27.149 29893 29893 E AndroidRuntime: FATAL EXCEPTION: main
08-01 19:44:27.149 29893 29893 E AndroidRuntime: java.lang.NullPointerException
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at example.yemeb.List$1$3.run(List.java:116)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:615)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:92)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at android.os.Looper.loop(Looper.java:137)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:4931)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:511)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:558)
08-01 19:44:27.149 29893 29893 E AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
这个日志显示错误发生在((LinearLayout) findViewById(relative)).addView(tv);在第116行
我的代码有什么问题?
由于下面的代码,
int relative2 = 0;
final int relative = relative2;
relative的值为0,这是最终值,不能更改。所以当你执行((LinearLayout) findViewById(relative))
时,它就变成了((LinearLayout) findViewById(0))
。由于没有与id 0关联的视图,因此无法获得对该视图的引用,因此该值为空。当你试图给它添加一个视图时,你会得到一个nullpointer异常
从文档中读取findViewById()。它说
从XML中查找由id属性标识的视图在onCreate(Bundle)中被处理。
如果找到则返回视图,否则返回null。
所以基本上在你的情况下,确保当你试图通过id找到一个视图,视图是存在于xml布局文件与适当的id分配给它。这样,当R.java
文件生成时,这个id将被映射为一个int值。